Association between cannabis use and result of COVID-19 testing among scholarised adolescents in Andalusia: A cross-sectional study

María-Carmen Torrejón-Guirado; Miguel Ángel Baena-Jiménez; Marta Lima-Serrano

doi:10.1371/journal.pone.0347098

. 2026 May 7;21(5):e0347098. doi: 10.1371/journal.pone.0347098

Association between cannabis use and result of COVID-19 testing among scholarised adolescents in Andalusia: A cross-sectional study

María-Carmen Torrejón-Guirado ¹, Miguel Ángel Baena-Jiménez ^2,^*, Marta Lima-Serrano ¹

Editor: Vincenzo De Luca³

PMCID: PMC13152148 PMID: 42096480

Abstract

Aims

The COVID-19 pandemic may have impacted cannabis use among the adolescent population. Therefore, it is important to understand the potential factors linking cannabis use to COVID-19 and vice versa, as well as the consumption patterns following the onset of COVID-19.

Methods

This study conducted in Andalusia, Spain. Although, 1,051 adolescents aged 14–18 years were included in this cross-sectional study, of these, the 89 (8.5%) reported testing positive for COVID-19, who were the main target for our analyses. Sociodemographic, psychological, and cannabis use variables, as well as COVID-19 testing positive, isolation and some perceptions about cannabis and COVID-19 were analysed. A binary logistic regression, was conducted to examine the association between COVID-19-related factors and controlled for sociodemographic and psychological variables, assessed estimations with cannabis use.

Results

Adolescents testing positive for COVID-19 are almost 2.89 times more likely to have used cannabis in the last month. Additionally, number of isolations was higher among cannabis users and positive testing. Cannabis users showed a lack of perceived risk that cannabis use could exacerbate COVID-19 and that cannabis’ smoke could spread COVID-19. Sharing cannabis among adolescents during the pandemic may increase the risk of COVID-19 transmission.

Conclusions

Informing whether adolescents who use cannabis may be more likely to test positive for COVID-19 can contribute to a better understanding of substance use patterns during a public health emergency. However, given the exploratory and cross-sectional nature of this study, as well as its limited and context-specific sample, the findings should be interpreted with caution. Despite this, we believe that this research may inform future studies exploring the impact of cannabis use among adolescents during public emergency situations in larger samples and other contexts.

Introduction

In March 2020, Spain declared a nationwide lockdown to contain the rapid spread of COVID-19. These measures led to profound healthcare and social disruptions, significantly affecting adolescents’ daily lives, including mobility restrictions, school closures, and reduced social interaction [1].

The World Health Organization (WHO) declared the end of the pandemic at the beginning of May 2023 [2]. However, during the pandemic, reported cases of COVID-19 were substantial [3]. Certain population groups, such as adolescents, tend to experience this disease in an asymptomatic manner or with milder symptoms [4,5], which may have complicated detection and reporting of positive cases in this population.

Moreover, the United Nations’ Annual Report for 2020 against drug abuse highlighted that most countries reported an increase in cannabis consumption during the COVID-19 pandemic [6]. Previous studies have reported that cannabis use was associated with an increased risk of hospitalization and ICU admission among individuals with COVID-19 [7]. Nevertheless, the extent to which cannabis use is associated with reporting testing positive for COVID-19 among adolescents remains insufficiently examined, particularly in Spain.

Cannabis consumption stands as the most widely used illicit drug among teenagers globally [8]. The global prevalence of cannabis use in the last year was 5.8% (corresponding to 12 million) among 15- and 16-year-old adolescents [9].

In Spain, adolescents aged 14–17 years reported that the prevalence of cannabis use is 20.7% and increasing to 35.6% at age 18. In Andalusia specifically, according to ESTUDES 2025 survey, the average age of initiation of cannabis use is 15.1 years. Furthermore, lifetime prevalence is 21%, and 11.6% report use in the past 30 days. Approximately 94% of users consume cannabis in the form of hand-rolled cigarettes. In Spain, these are typically prepared by mixing cannabis (frequently in the form of hashish) with tobacco [10].

However, it is worth noting that in previous reports from 2022, which analyzed the impact of the pandemic in Andalusia, ESTUDES survey reported a decline in cannabis use, attributing this primarily to the pandemic (e.g., due to mobility restrictions) [10]. These data coincide with the OEDA-COVID 2020 survey, which was conducted on the general population residing in Spain, with fieldwork carried out between November 10 and December 3, 2020 [11]. This telephone survey identified a change in cannabis consumption patterns, revealing that 3.5% of the population either stopped using cannabis or reduced their consumption during the pandemic, with this percentage being higher among men than women. However, ESTUDES 2022 reported that cannabis use prevalence had progressively increased as social outings, particularly nighttime activities, had resumed [12].

Despite this evolving evidence, few studies have specifically examined the association between cannabis use and reporting testing positive for COVID-19 among adolescents. A recent systematic review summarize cannabis use among adolescents during the COVID-19 pandemic [13]. Yet, few studies give importance in the first instance to the COVID-19 testing positive. For instance, other scoping review explored the impact of cannabis consumption on COVID-19 in a predominantly adolescent population, concluding that the validity of studies conducted thus far was insufficient to establish accurate associations [14]. International studies emphasized the importance of investigating the association between COVID-19 testing positive and cannabis consumption in adolescents [15,16]. However, no studies were found that linked COVID-19 and recreational cannabis use in adolescents in Spain.

Given that COVID-19 is still prevalent, and cannabis consumption continues to rise each year, it is necessary to conduct studies in this context to explore factors related to COVID-19 and cannabis consumption in adolescents.

The study

To address this gap, a cross-sectional study was conducted in Sevilla, Cádiz, Córdoba, and Huelva. Andalusia is the largest autonomous community in Spain, covering approximately 87,600 km², with a diverse population spread across urban and rural areas [17]. This geographical and demographic variability poses challenges for conducting studies, including participant recruitment and accessibility, so that we decided to include Western Andalusian participants.

The hypothesis generation posits that the result of COVID-19 testing positive among Western Andalusian adolescents will have a positive epidemiological correlation with cannabis use. Yet, the variables that are related to this hypothesis may differ per frequency of cannabis use, age, and other factors. Therefore, the objectives of this study are: (1) to identify putative cannabis use associated with COVID-19 testing positive in a sample of Andalusian students aged 14–18 and (2) to explore correlations between cannabis use and testing positive COVID-19 and behavioural variables related with COVID-19 (such as isolations and sharing cannabis during the pandemic) as well as perceptions about the relationship of COVID-19 and cannabis use.

Materials and methods

Design and population

A random sample was collected from the clusters of 21 high schools from both rural and urban settings of four provinces of Western Andalusia. The sample size was calculated using the online tool GRANMO (Result 1046, accepting an Alpha risk of 0.05 and Beta of 0.2 in a bilateral test). The sample was randomly selected through cluster sampling. The recruitment started on 01-05-2021 and the end of the recruitment period for this study was 30-06-2021.

Inclusion criteria were adolescents aged 14–18 years, and adolescents from educational level of 9th–12th grade or vocational training (VT). Duplicate or incomplete questionnaires were excluded. Responses were obtained from a total of 1086 students, of which 1051 met the inclusion criteria (484 male students and 567 female students) (Fig 1).

Measurements

For better comprehension, the variables were divided into three groups: the sociodemographic and psychological variables, behavioural variables (such as isolations or sharing cannabis during the COVID-19), and the more subjective variables related to COVID-19, referring to the adolescent#39;s perceptions. In addition to the two main outcomes of the article: testing COVID-19 and cannabis use.

Testing COVID-19.

The following ad hoc questions were designed to explore the relationship of COVID-19 to cannabis use: COVID-19 testing positive (0 = no, 1 = yes).

Cannabis consumption.

The Spanish ESTUDES survey was used to assess cannabis consumption by asking two different questions: “Do you consume cannabis?,” and “Have you ever consumed cannabis/marijuana, even if it was just a puff from a joint among friends [“In your life,” “In the last 12 months,” and “In the last 30 days”]?” Responses were coded as follows: (0 = no cannabis use), (1 = I used cannabis 1 day), (2 = 2 days), (3 = 3 days), (4 = 4–5 days), (5 = 6–9 days), (6 = 10–19 days), and (7 = 20 days or more) [19].

Sociodemographic and psychological variables.

Age (in years), gender (female (1) or male (0)), educational level (9^th–12^th grade or VT) and academic performance (0%–39%, 50%–59%, 60%–69%, 70%–79%, 80%–100%).

Rosenberg Self-Esteem Scale with 10 questions (1 “strongly disagree” to 4 “strongly agree”; reverse coding: items 2, 6, 8, and 9) (Cronbach’s α = 0.459) [20], and personality, assessed using the Substance Use Risk Profile Scale with 23 questions (1 “strongly disagree” to 4 “strongly agree”; reverse coding: items 1, 4, 7, 13, 20, and 23) and with a four-dimensional component: hopelessness, impulsiveness, sensation seeking, and sensitivity anxiety (Cronbach’s α = 0.737) [21].

Behavioural variables.

Number of isolation (0–10). Have you shared cannabis during the COVID-19 pandemic? (0 = no, 1 = yes).

Perception variables associating COVID-19 with cannabis use.

Do you think that cannabis worsen COVID-19? (0 = no, 1 = yes); Do you think that cannabis smoke spread COVID-19? (0 = no, 1 = yes). Perception variables related to the consumption of other substances from the OEDA-COVID 2020 survey served as a reference for designing our questions [22,23].

Procedure

Using the Andalusian Regional Government website, a comprehensive list of all schools in the mentioned provinces was obtained. Randomly, an equal number of public and private high schools, as well as an equal number of rural and urban secondary education institutions (IES), were selected. Following this selection, telephonic and email contact was established with the directors of 87 IES to request their collaboration, with responses received from 20 directors. Subsequently, based on the school#39;s protocols, directors directed us to the guidance department, facilitating our communication with the guidance counsellors. Preliminary information regarding this study, along with the informed consent and questionnaire, was dispatched to the school directors and guidance counsellors. Once their participation was confirmed, specific dates were arranged to conduct the questionnaires, allowing us to collect data from the selected sample. This process occurred via virtual platform (Le Sphinx) or in-person visits, consistently during school hours and with oversight from responsible teachers to ensure the agreed-upon procedures were carried out with the utmost assurance.

Participants consent and ethics statement

All participants provided their written informed consent. Participants were instructed that they could chose not to complete the survey. Active written consent was requested from parents, unless the high school indicated that they wanted to provide passive written consent. Parents were notified in writing at least one week in advance of data collection, so they could opt out their adolescent from data collection.

This observational study was approved by the Andalusian Research Ethics Committee (registration number: 0073-N-18) in 2018. The confidentiality of the data was guaranteed and explained to the participants and their parents, and the procedures followed the Regulation (EU) 2016/679 of the European Parliament and the Data Protection Council. In addition, during the design of the study, the data protection delegate of the University of Seville was contacted to carry out the corresponding procedures on the treatment of data of minors. This study was performed in line with the principles of the Declaration of Helsinki, and its later amendments or comparable ethical standards.

Statistical analyses

To verify the normal distribution of the selected variables, the Kolmogorov-Smirnov test was conducted. A descriptive study was performed to calculate frequencies and percentages for qualitative variables, and means and standard deviations for quantitative variables. Additionally, a bivariate analysis was conducted: the Chi-Square test was used to determine the independence between two qualitative variables, and the T-Student test was employed to compare the independence between a quantitative and a qualitative variable.

To assess how well the measured factors are associated with cannabis use, binary logistic regression analysis was conducted [24]. All variables were included in the model, except for the educational level, because it had the largest p-value in the chi-square test. Personality and self-esteem were used as index because of their multidimensional nature. The level of significance was set at p < 0.05, and the enter method was used in this study. As there were very few missing values, no imputation data was performed. This statistical analysis was conducted using Statistical Package for the Social Sciences [25].

Results

Study sample characteristics and COVID-19 testing positive

Out of a total of 1,051 adolescent participants with an average age of 15.29 years, where 27% (N = 284) of the participants were 14 years old, 29.9% (N = 314) were 15 years old, 24.9% (N = 262) were 16 years old, 15.3% (N = 161) were 17 years old, and 2.9% (N = 30) were 18 years old. Moreover, 53.9% (N = 567) were female.

The academic performance of the participants showed an average score of 2.10, that indicates that the majority of participants demonstrated good academic performance. Participants reported having an average self-esteem score of 28.78 (SD = 3.936), indicating a moderate level of self-esteem among the surveyed students, with no severe self-esteem issues observed (see Table 1).

Table 1. Sociodemographic, psychological, and related COVID-19 and cannabis behaviour and perception description of the sample and its correlation with adolescents’ COVID-19 testing positive.

Variables	Participants N = 1051	Negative COVID-19 N = 961	Positive COVID-19 N = 89	T-test o χ2	P valor of t-test o χ2
*Sociodemographic and psychological*
Schools	N = 20
Age (14–18) (mean, SD) (m 9)	15.29 (1.289)	15.29 (1.302)	15.22 (1.149)	0.520	0.603
Gender (m 0)
• Male • Female	484 (46.1%) 567 (53.9%)	440 (45.8%) 521 (54.2%)	44 (49.4%) 45 (50.6%)	0.437	0.291
Adolescents Educational Level (m 0)
• 10th Grade • 11th Grade • Vocational Training (VT)	697 (66.3%) 302 (28.7%) 52 (5%)	635 (66.1%) 278 (28.9%) 48 (5.0%)	62 (69.7%) 23 (25.8%) 4 (4.5%)	0.469	0.791
Academic Performance (mean, SD) (m 1)	2.10 (0.970)	2.09 (0.971)	2.31 (0.937)	−2.127	0.034
Self-esteem (mean, SD) (m1)	28.78 (3.936)	28.76 (3.929)	29.00 (4.009)	−0.551	0.582
Risk Profile of Substance Use (mean, SD) (m 1)
• Hopeleness	21.04 (3.444)	20.99 (3.439)	21.69 (3.459)	−1.833	0.067
• Impulsivity	11.86 (3.207)	11.90 (3.192)	11.44 (3.364)	1.288	0.198
• Sensation Seeking	16.63 (3.968)	16.58 (3.964)	17.21 (4.001)	−1.441	0.150
• Axiety	12.09 (3.226)	12.12 (3.174)	11.69 (3.740)	1.044	0.299
*Behavioural*
Isolation (mean, SD) (m 1)	0.74 (0.968)	0.68 (0.949)	1.36 (0.956)	−6.444	<0.001
Sharing Cannabis in Pandemic (m 158) • No • Yes	893 (93.0%) 67 (7.0%)	818 (93.1%) 61 (6.9%)	75 (92.6%) 6 (7.4%)	0.025	0.506
*Perceptions*
Cannabis’ Smoke Contagious (m 1) • No • Yes	180 (17.1%) 870 (82.9%)	169 (17.6%) 792 (82.4%)	11 (12.4%) 78 (87.6%)	1.566	0.133
Cannabis Worsening COVID-19 (m 1) • No • Yes	297 (28.3%) 752 (71.6%)	275 (28.6%) 686 (71.4%)	22 (24.7%) 66 (75.3%)	11.323	0.003

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m = missing values, N = sample size, T-Test = Student#39;s t-test, χ² = Chi-squared test.

Regarding the Risk Profile for Substance Use, the average scores were Hopelessness (M = 21.04, SD = 3.444), Impulsivity (M = 11.86, SD = 3.207), Anxiety (M = 12.091, SD = 3.226), and Sensation Seeking (M = 16.63, SD = 3.968). There was no specified cut-off points provided by the author, nor any other studies to use as a reference, and due to the absence of a comparison group, it is not possible to determine if these values are low, medium, or high.

The COVID-19 testing was negative in 91.4% (N = 961) of the participants and positive in 8.5% (N = 89). The average number of isolations was 0.74 (SD = 0.968) and 67 participants reported sharing cannabis during the pandemic (7.0%). Table 1 also shows the factors associated with the COVID-19 testing positive. COVID-19 testing positive was associated with higher academic performance and a higher number of isolations due to close contact with positive individuals.

Regarding the perception data associating the COVID-19 with cannabis use, 870 participants believed that cannabis smoke spreads the disease (82.9%), and 752 believed that cannabis use worsens COVID-19 (71.6%). COVID-19 testing positive was associated with a positive perception that cannabis use would worsen COVID-19.

Cannabis use and estimated factors

From the total sample (Table 2), 669 participants (63.6%) were identified as non-cannabis users and 382 participants (36.4%) as cannabis users at some point in their lives. Over the last year, 887 participants (84.4%) were identified as non-cannabis users and 164 participants (15.6%) as cannabis users. In the last month, 895 participants (85.2%) were identified as non-cannabis users and 156 participants (14.8%) as cannabis users.

Table 2. Sociodemographic, Psychological, and COVID-19 Variables Related to Cannabis Use in Adolescents.

	LifeTime			Last Year			Last Month
Variables	Non-Users N = 669	Cannabis Users N = 382	T-test o χ2. P valor	Non-Users N = 887	Cannabis Users N = 164	T-test o χ2. P valor	Non-Users N = 895	Cannabis Users N = 156	T-test o χ2. P valor
COVID-19 testing (m 1) • No (negative) • Yes (positive)	619 (92.5%) 50 (7.5%)	342 (89.8%) 39 (10.2%)	χ2 (2.388). 0.077	820 (92.4%) 67 (7.6%)	141 (86.5%) 22 (13.5%)	χ2 (6.270). 0.012	827 (92.5%) 67 (7.5%)	133 (85.8%) 22 (14.2%)	χ2 (7.662). 0.007
*Sociodemographic and psychological*
Age (14–18) (mean, SD)(m 9)	15.21 (1.261)	15.41 (1.330)	T (−2.436). 0.015	15.30 (1.290)	15.21 (1.288)	T (0.820). 0.410	15.30 (1.295)	15.18 (1.256)	T (1.093). 0.275
Gender (m 0)
• Male	309 (46.2%)	175 (45.8%)	χ2 (0.014). 0.479	476 (53.7%)	91 (55.5%)	χ2 (0.85). 0.366	413 (43.1%)	71 (45.5%)	χ2 (0.021). 0.477
• Female	360 (53.8%)	207 (54.2%)	χ2 (0.014). 0.479	411 (46.3%)	73 (45.5%)	χ2 (0.85). 0.366	482 (53.9%)	85 (54.5%)	χ2 (0.021). 0.477
Adolescents Educational Level (m 0)
• 10th Grade • 11th Grade • Vocational Training (VT)	455 (68.0%) 184 (27.5%) 30 (4.5%)	242 (63.4%) 118 (30.9%) 22 (5.8%)	χ2 (2.566). 0.277	579 (65.3%) 263 (29.7%) 45 (5.1%)	118 (72.0%) 39 (23.8%) 7 (4.3%)	χ2 (2.771). 0.250	583 (65.1%) 266 (29.7%) 46 (5.1%)	114 (73.1%) 36 (23.1%) 6 (3.8%)	χ2 (3.752). 0.153
Academic Performance (mean, SD) (m 1)	2.06 (0.934)	2.18 (1.027)	T (−1.807). 0.071	2.08 (0.953)	2.24 (1.050)	T (−1.915). 0.056	2.08 (0.953)	2.26 (1.053)	T (−1.978). 0.034
Self-esteem (mean, SD)(m 1)	28.73 (3.787)	28.85 (4.187)	T (−0.485). 0.628	28.81 (3.901)	(4.123)	T (0.608). 0.543	28.80 (3.914)	28.61 (4.068)	T (0.572). 0.567
Risk Profile of Cannabis Use (mean, SD) (m 1)
• Hopelessness	21.04 (3.447)	21.04 (3.444)	T (−0.013). 0.990	21.11 (3.468)	20.67 (3.301)	T (1.485). 0.138	21.11 (3.465)	20.63 (3.303)	T (1.609). 0.108
• Impulsivity	11.76 (3.142)	12.02 (3.315)	T (−1.264). 0.206	11.72 (3.165)	12.59 (3.342)	T (−3.192). 0.001	11.73 (3.161)	12.58 (3.378)	T (−3.063). 0.002
• Sensation Seeking	16.20 (3.897)	17.39 (3.981)	T (−4.746). < 0.001	16.36 (3.969)	18.09 (3.644)	T (−5.153). < 0.001	16.38 (3.961)	18.11 (3.685)	T (−5.083). < 0.001
• Anxiety	12.055 (3.177)	12.152 (3.312)	T (−0.468). 0.640	12.106 (3.260)	12.006 (3.038)	T (0.363). 0.717	12.126 (3.267)	11.884 (3.041)	T (0.864). 0.388
*Behavioural*
Isolation’s number (mean, SD) (m 1)	0.69 (0.947)	0.83 (0.998)	T (−2.221). 0.27	0.71 (0.955)	0.88 (1.027)	T (−2.076). 0.038	0.71 (0.953)	0.92 (1.035)	T (−1.564). 0.0010
Sharing Cannabis in Pandemic (m 158)
• No	740 (82.86%)	153 (17.13%)	χ2 (102.87)	846 (94.74%)	47 (52.6%)	χ2 (309.91)	797 (89.24%)	96 (10.76%)	χ2 (275.128)
• Yes	5 (7.46%)	62 (92.53%)	<0.001	25 (37.31%)	42 (62.68%)	<0.001	8 (11.94%)	59 (88.06%)	<0.001
*Perceptions*
Cannabis’ Smoke Contagious (m 1) • No • Yes	101 (15.1%) 568 (84.9%)	79 (20.7%) 302 (79.3%)	χ2 (5.432). 0.013	136 (15.3%) 751 (84.7%)	44 (27%) 119 (73%)	χ2 (13.183). < 0.001	137 (15.3%) 758 (84.7%)	43 (27.7%) 112 (72.3%)	χ2 (14.382). < 0.001
Cannabis Worsening COVID-19 (m 1) • No • Yes	150 (22.4%) 518 (77.4%)	147 (38.6%) 234 (61.4%)	χ2 (31.674). < 0.001	211 (23.8%) 675 (76.1%)	86 (52.8%) 77 (47.2%)	χ2 (57.060). < 0.001	214 (23.9%) 680 (76.0%)	83 (53.5%) 72 (46.5%)	χ2 (57.284). < 0.001

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m = missing values, N = sample size, T-Test = Student#39;s t-test, χ² = Chi-squared test.

Among the sociodemographic and psychological variables, the only variable that was significantly associated with cannabis use across all three periods was the personality trait of sensation seeking, which had a higher mean in users compared to non-users. For cannabis use in the last month and the last year, a positive association was also found with the trait of impulsivity. Academic performance was associated with cannabis use in the last month, interestingly showing higher performance among users. Age was significantly positively associated with lifetime cannabis use.

COVID-19 testing positive was significantly associated with cannabis use in the last year, last month, and marginally with lifetime use. In all instances, the risk of COVID-19 testing positive was higher in users compared to non-users. Additionally, perceptions such as “cannabis smoke transmits COVID-19” and “cannabis use worsens COVID-19” were correlated with the three frequencies of cannabis use: lifetime, last year and last month. For instance, cannabis users showed a slightly lower perception that cannabis’ smoke could spread COVID-19 compared to non-users. However, non-cannabis users reported having favorable perceptions about cannabis use could worsen COVID-19 compared to users, who reported to have the perception that cannabis could not worsen COVID-19. Finally, the mean number of isolations was higher among users in the last year and the last month.

Relationship of COVID-19 testing positive and Cannabis Use

The Odds Ratio (OR) was calculated for all three period of time, being respectively: 1.9096, 95% CI = 1.1425 to 3.1918 for lifetime cannabis use, 2.0417, 95% CI = 1.2196 to 3.4180 for last year cannabis use, and 1.4118, 95% CI = 0.9101 to 2.1900 for last month cannabis use.

In the regression analysis, sharing cannabis during the pandemic and not having the perception about cannabis worsens COVID-19, were related to cannabis use in all the explored frequencies of cannabis use (lifetime, last year and last month). For last month cannabis use, a COVID-19 testing positive was also associated with cannabis use (OR=2.898). Nagelkerke#39;s indicator of explained variance was 40% for last month cannabis use (Table 3).

Table 3. Resultant Variables in Logistic Regression Analysis for Cannabis Consumption on Adolescents.

Variables	Lifetime				Last Year				Last Month
	p	OR	IC 95%		p	OR	IC 95%		p	OR	IC 95%
			Inf	Sup			Inf	Sup			Inf	Sup
Testing COVID-19 (yes VS no)	.206	1.390	.834	2.317	.325	1.581	.636	3.932	.001	2.898	1.525	5.507
*Behavioural*
Number Isolations	.778	1.014	.918	1.121	.961	.996	.835	1.187	.962	1.003	.870	1.158
Share Cannabis During Pandemic (no VS yes)	<.001	51.688	12.420	215.098	<.001	21.663	11.388	41.208	<.001	64.302	27.033	152.949
*Perceptions*
Cannabis’ Smoke contagious COVID-19 (no Vs yes)	.709	1.082	.717	1.632	.311	.720	.381	1.360	.425	.800	.462	1.385
Cannabis Worsens COVID-19 (no VS yes)	<.001	.538	.382	.757	.001	.390	.220	.691	<.001	.386	.241	.616
Chi-square omnibus	164.121 (<.001)				173.603 (<.001)				256.995 (<.001)
Nagelkerke R ²	.216				.363				.404

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95% IC = 95% confidence interval; OR= odds ratio; p = p value. The analyses were controlled for sociodemographic and psychological variables.

Discussion

This study is the first conducted in Andalusia to explore the estimated association between reporting COVID-19 testing positive and using cannabis among Andalusian adolescents aged 14–18, across three different cannabis use’ periods: lifetime use, use in the last year, and using in the last month. Additionally, this article addresses one of the knowledge gaps identified by Torrejón-Guirado in previous studies: the pandemic situation and its relationship with cannabis use [26].

Regarding the prevalence of cannabis use, our results showed that lifetime cannabis use was higher among females than males, while in ESTUDES 2023 showed that lifetime cannabis use was higher among males [10]. Furthermore, looking at the last month cannabis use, while our results showed similar outcomes to those observed over a lifetime cannabis use (i.e., higher consumption in females), ESTUDES survey indicated that the prevalence of cannabis use was nearly twice as high among males (1.7%) compared to females (1%) [10].

Regarding the estimated association between reporting COVID-19 testing positive and using cannabis, the OR for cannabis use in the last month and COVID-19 testing positive was 2.898, suggesting that individuals diagnosed with COVID-19 are almost three times more likely to have used cannabis in the last month. Yet, the Nagelkerke R² values suggest that 60% of the variability is attributed to factors not accounted for in the model, especially in the case of lifetime and last-year cannabis use. Thus, caution is requested in the interpretation of the data, as well as when interpreting the confidence coefficients (some intervals were wide, reducing the statistical significance). Nevertheless, our finding is in line with a study which reflected that 52% of those students (aged 18–26) who smoked electronic cigarettes and cannabis were 1.85 times more likely to be diagnosed with COVID-19 [16]. Additionally, the fear of COVID-19 testing positive has been linked to increased cannabis use [27].

Regarding the perception of “cannabis worsens COVID-19”, our finding suggests on one hand, that this perception is slightly higher in those who have had COVID-19 (75.3%) compared to those who have not had it (71.4%), and on the other hand, individuals who do not endorse this belief are more likely to use cannabis. However, no research has previously studied the associations between beliefs about the impact of cannabis use on this infectious disease. Although our study cannot conclude that cannabis use worsens COVID symptoms, a study (n = 13,099) of adults showed that the frequency of cannabis use could be considered a possible predictor of COVID-19 mortality risk [28]. So, giving the relevance of this finding, it would be beneficial to conduct studies in adolescent population to implement health recovery and prevention measures. These measures could include informational sessions for adolescents about the consequences of cannabis use on COVID-19 testing positive, highlighting the increased probability of developing respiratory issues such as severe pneumonia, and basing also on relevant guidelines such as Parrado-Gónzalez et al., mainly, as far as Andalusia and Spain are concerned [29]. Moreover, a retrospective study found that adult users of substances such as cannabis and tobacco are significantly more vulnerable to COVID-19 and its complications, making them more likely to require hospitalization and face and increased risk of death compared to non-users [30]. We recommend investigating a possible causal association between a low perception that cannabis worsens COVID-19 and the presence of the disease. As low-risk perception has been widely studied in the literature as a relevant in the adoption of risky behaviours, it may also impact the acquisition/progression of the disease. This highlights the importance of addressing such beliefs through health education.

Educational interventions could play a relevant role in preparing the population for future pandemics by anticipating the consequences of COVID-19, particularly for individuals with pre-existing conditions affecting the respiratory system. Some of these measures could include sharing information through adolescent and young adult consumers who have experienced hospitalization and suffered significant health effects due to the progression of the disease after being diagnosed. Moreover, misconceptions about cannabis and COVID-19 may arise from incomplete information, such as media reports suggesting a potential protective effect or the known anti-inflammatory properties of cannabidiol (CBD) [31]. Some adolescents might wrongly assume that cannabis consumption enhances immunity or mitigates severe inflammatory responses associated with COVID-19. These misinterpretations highlight the need for clear, evidence-based education on cannabis and its actual health effects.

In relation to the higher frequency of isolations among cannabis users, no studies have been identified that directly analyse the relationship between the number of isolations and the likelihood of testing a positive COVID-19, while several studies have suggested that individuals who self-isolated during the COVID-19 pandemic might have increased their cannabis consumption due to the emotional distress caused by isolation [32–34]. Cannabis use may have risen during isolations due to factors such as stress, anxiety, depression, and boredom. However, a more thorough understanding of this reality should be pursued, with questions that allow for a broader exploration of these factors, since it is also possible that individuals who use cannabis may have more positive test results and, consequently, more isolations. Although the interaction has not been studied, this interpretation is plausible and could occur, while always considering the limitations of our exploratory analysis.

Regarding the correlation of COVID-19 testing positive and having a good academic performance, similar to our results, a study conducted in China (n = 1316) with high school students found that, despite isolation due to COVID-19, the students maintained high academic performance [35]. This could be because these studies were conducted approximately one year after the state of emergency. Therefore, educational institutions prepared themselves and provided their students with tools to ensure their academic performance. Despite that isolation encompasses numerous barriers to potential academic development, such as difficulties in accessing adequate computing and technology, distracting home environments, and the socio-emotional cost of isolation [32,36,37]. This estimated association would therefore need to be analysed in depth, for instance, through longitudinal studies.

Finally, interesting correlations were found between cannabis use and certain behavioural (sharing cannabis during the pandemic and isolations) and perceptions variables related to COVID-19 (cannabis smoke contagion COVID-19 and cannabis worsening COVID-19) in bivariate and multivariate analysis. For instance, concerning the perceptions of “cannabis smoke contagion COVID-19”, no published studies were found that examined the possible association between the perception that “cannabis smoke could transmit COVID-19” and using cannabis, either than COVID-19 testing. However, in the context of tobacco, tobacco smoke has been shown to facilitate COVID-19 transmission [38,39]. To prevent the spread of COVID-19, it may be relevant for adolescents to understand the harmful consequences of group cannabis use during COVID-19 outbreaks in their environments.

At last, it should be considered that as the adolescents’ responses are based on perceptions rather than experiences, it should also be considered that cannabis users may respond in a socially desirable manner, aligning with perceived health norms to minimize potential health harm. Nevertheless, and given the estimated association found, it is important that educators and nurses explain to them that the consequences of having COVID-19 while using cannabis could be detrimental for health. It would also be relevant to study the differences between the effects of CBD and THC separately to obtain clearer conclusions, as some existing literature suggests that CBD could be a protective factor against COVID-19 [40].

Strengths and limitations

One limitation of this study is its cross-sectional design. We recommend conducting longitudinal studies to establish causal relationships regarding cannabis use through these factors. Furthermore, the study#39;s reliance on a limited sample of participants who tested positive for COVID-19 (N = 89) restricts the statistical power and generalizability of the findings. A second limitation is that, due to the contemporary nature of the study topic, the questions related to COVID-19 have not been previously validated (potential recall bias or tic errors). It would thus be advisable to design and validate a tool to measure COVID-19-related variables in relation to cannabis consumption. Given that this study occurred during the pandemic with unusual measures in place, most secondary schools did not allow in-person studies, preventing close interaction with students. The third limitation is related to the Rosenberg scale. Although it is a previously validated instrument, our study found a Cronbach#39;s alpha of 0.459. Yet, no studies have been found reporting Cronbach’s alpha as low as 0.5 when applied to adolescents. Such a low reliability coefficient could indicate issues related to scale administration, item comprehension, or cultural adequacy of the instrument. It is possible that the low Cronbach’s alpha is influenced by adolescents’ self-perception of their own self-esteem. Given the sensitive and personal nature of self-esteem, adolescents may struggle to respond honestly, particularly in contexts where expressing vulnerability is socially discouraged. Furthermore, difficulties in instrument administration, such as lack of privacy or social pressure during responses, may also contribute to lower reliability estimates.

Additionally, although the regression analysis controls for sociodemographic and psychological variables, there may be other unmeasured confounding factors influencing the results (e.g., the social environment in which cannabis use occurs, which could significantly impact both COVID-19 risk, or other factors such as cannabis use patterns, cannabis’ products, family dynamics or mental health). In fact, the multivariate analysis suggests that 60% of the variability is attributed to factors not accounted for in the model, especially in the case of lifetime and last-year cannabis use. Thus, caution is requested in the interpretation of the data, as well as when interpreting the confidence coefficients (some intervals were wide, reducing the statistical significance).

It should also be considered that the results of this study should be interpreted with caution, as it is based on a self-reported survey (i.e., reporting bias), where data on the specific types of cannabis products (such as herb, resin, CBD) and methods of consumption (such as vaping or oral intake) were not specified. Moreover, in Spain, as in other countries, there is a partial regulation of cannabis supplies. For instance, low-dronabinol (delta-9-THC) cannabis products are available, which may contribute to a reduced risk perception of cannabis use among youth [35]. Furthermore, considering these trends, new therapeutic approaches focusing on harm reduction are increasingly being adopted by health practitioners and should be considered. Future research could explore these variables to provide a more comprehensive understanding of the relationship between cannabis use and COVID-19 outcomes, as well as potential strategies to mitigate the impact of substance use on infection rates. They also could consider reclassifying participants into mutually exclusive groups (no use = 669; last-month use = 156; use more than one month ago = 226) and conducting supplementary multinomial logistic regression analyses.

Finally, a selection bias is that the recruited participants were school adolescents. It would be recommended to include adolescents who not attend school since they may have different characteristics. A last limitation is the variable “sharing cannabis during the pandemic” should be also interpreted with caution, as the self-administered survey did not specify whether it referred to just a single puff, an entire joint, or other details such as a cannabis-containing cigarette. Future studies aiming to investigate the relationship between COVID-19 and shared cannabis use, in order to determine whether it increases transmission, should take these considerations into account.

The primary strength of this study is that no other studies in Spain have been found to relate cannabis consumption with COVID-19 variables, such as COVID-19 testing positive. Diagnosing COVID-19 in people who use cannabis helps protect respiratory and immune health, allows for better symptom and treatment management, and reduces the risk of complications. Another strength is the heterogeneity of the sample and its sufficient size. Different frequencies for measuring cannabis consumption were also included, allowing for a closer approximation to the reality of this context in Andalusia. A final strength of this study is that, despite the small sample size of participants who reported testing positive for COVID-19, significant cross-sectional estimated associations were found with two variables.

Conclusion

The findings of this exploratory study provide additional context-specific data regarding cannabis use among adolescents in Western Andalusia during the COVID-19 pandemic. An estimated association was observed between COVID-19 positivity and cannabis use, particularly last-month consumption where the odds was almost three points higher. Moreover, cannabis users showed a slightly lower perception that cannabis’ smoke could spread COVID-19 while non-cannabis users reported having favorable perceptions about cannabis use could worsen COVID-19. This perception is also higher in those that were positive testing COVID-19. Finally, the mean number of isolations was higher among cannabis users and positive testing. As consuming cannabis has been identified as a predictor of COVID-19 hospitalization and mortality risk we think that our study gives some context-insights that could be relevant for preparing for future public health emergencies and for informed future large scale research. It is also important of leverage the conscientious about the effect of cannabis use among adolescents and their context, which can be exacerbated in a pandemic situation.

Data Availability

The data underlying the results presented in the study are available from Zenodo (a public repository; accession DOI: https://doi.org/10.5281/zenodo.15106665).

Funding Statement

This work was supported by the University of Seville research program (VPPI-US) in terms of a pre-doctoral contract of Torrejón-Guirado. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Additionally, this was a secondary objective of a nationally funded project by the Spanish Ministry of Science, Innovation, and Universities under the “State Plan 2017-2020 Challenges - R&D&I Projects” call, titled “Cannabis Alert: Evaluation of a Tailored Computer-Based Intervention for the Prevention of Cannabis Use in Adolescents Aged 14 to 18 Years” (PID2019-107229RA-I00). This funder also had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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PLoS One. doi: 10.1371/journal.pone.0347098.r001

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-->PONE-D-24-49229-->-->COVID-19 and cannabis use in students from 14 to 18 years old: addressing its related factors.-->-->PLOS ONE

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Reviewer #1: -Research Summary and General Impression

The study examines sociodemographic, psychological, and behavioral variables related to cannabis use and COVID-19 diagnosis in adolescents. While the results are interesting, the cross-sectional design limits causal conclusions.

-Strengths:

Real-world observational study providing insights into behaviors during the pandemic.

Considerable and diverse sample size.

-Major Issues:

COVID-19 Diagnosis Validation: Lack of diagnostic testing may affect result validity.

Causality: Avoid claims of “strong association” and emphasize that the study generates hypotheses rather than establishing causation.

-Minor Issues:

Descriptive Statistics: Include detailed age distribution and other sociodemographic variables.

STROBE Checklist: The article mentions a flowchart but omits the full checklist.

-The study presents results from primary scientific research:

The study is a cross-sectional observational study (survey), suitable for generating hypotheses. Clarify the study type in the methods section to prevent misunderstandings regarding causality.

-The reported results have not been published elsewhere:

It is unclear if the results are novel. The authors should explicitly if the findings have not been submitted elsewhere to avoid duplication.

-Experiments, statistics, and other analyses are conducted to a high standard and described in sufficient detail:

Number of Participants: Adolescents aged 14-18 were included. Specify how many participants were under 18 and clarify how parental informed consent (IC) was obtained. Provide details on "passive consent" to ensure ethical compliance.

Descriptive Analysis: Only the median age is given. Include a percentage distribution of ages for a more comprehensive sample understanding.

-Conclusions are appropriately presented and supported by data:

COVID-19 Diagnosis: Diagnosis was based on a binary question ("Yes/No"), with no confirmatory testing. Discuss the limitations of this method and potential recall bias or diagnostic errors.

Association vs. Causation: The study suggests an association between COVID-19 diagnosis and cannabis use, but cross-sectional design limits causal inference. Replace terms like "association" with "estimate" or "hypothesis generation" to reflect the study's nature.

Severity of COVID-19: Consider including information on the severity of COVID-19 cases among participants.

-The article is intelligible and written in standard English:

The article is well-written. Consistently replace “association” with “estimate” or “hypothesis generation” where appropriate.

-The research meets ethical standards and research integrity:

Minor Consent: For ages 14-18, clarify how parental informed consent was obtained. Confirm if all minors had signed consent from guardians.

-The article adheres to appropriate reporting guidelines and community standards for data availability.

STROBE Checklist: The article mentions a flowchart but omits the full checklist.

-Requests:

1.STROBE checklist to ensure all relevant observational study items are addressed.

2.Confirm if 100% of parental or legal guardian consents were obtained for minors.

3.Suggest more detailed statistical descriptions of the sample, particularly age distribution.

4.Replace terms like "association" with "estimate" or "hypothesis generation" to reflect the study's nature.

5.COVID-19 Diagnosis Validation: Lack of diagnostic testing may affect result validity. Discuss the limitations of this method and potential recall bias or diagnostic errors.

Reviewer #2: The full review exceeds 20,000 characters, and is placed in attachement.

Conclusion:

"[…] In conclusion, while the study explores a relevant and timely topic, it fails to meet the necessary standards of scientific rigour for publication in PLOS ONE as such. The manuscript's primary limitations include:

- The use of outdated epidemiological data, specifically from the 2018 Spanish National Plan on Drugs survey (ESTUDES), neglecting more recent and relevant studies such as the 2023 ESTUDES report and the 2024 EDADES report. This failure to incorporate the most current data undermines the study's contextualisation and relevance.

- A lack of precision and clarity in the formulation of the research questions and the interpretation of results, for example, using the term "students" when "adolescents" may be more appropriate, the poorly defined hypothesis, and ambiguous wording concerning cannabis sharing.

- An over-reliance on a small sample of participants who tested positive for COVID-19 (N=89), which limits the statistical significance and generalizability of the findings.

- A problematic mixing of objective and subjective data, most evident in Table 1, which makes interpretation difficult.

- The lack of a thorough discussion of harm reduction strategies, which have been proven to be effective and should be considered when addressing youth cannabis use

- A tendency to draw strong conclusions from weak associations, such as the suggestion of links between school absenteeism and COVID-19.

Overall, the manuscript needs substantial revision to address these critical issues. A more robust methodology, clearer research questions, up-to-date data, and a more nuanced discussion of the findings are required before this study can be considered a valid contribution to the scientific record. Without these fundamental improvements, the conclusions drawn from the data remain questionable."

**********

-->6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.-->

Reviewer #1: Yes:Cláudio Calixto Carlos da Silva

Reviewer #2: No

**********

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PLoS One. 2026 May 7;21(5):e0347098. doi: 10.1371/journal.pone.0347098.r002

Author response to Decision Letter 1

1 Apr 2025

Dear reviewers,

We have uploaded 4 new documents: the revised manuscript with tracks and without tracks changes, and other two documents answering the reviewers comments (they are named as: "answer to reviewer 1" and "answer to reviewer 2").

We appreciate your valuable comments to achieve and to improve the quality of the manuscript.

Best regards

Miguel Ángel Baena Jiménez

Attachment

Submitted filename: Answer to reviewer 2.docx

pone.0347098.s002.docx^{(49.3KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0347098.r003

Decision Letter 1

David Adedia

17 Sep 2025

-->PONE-D-24-49229R1-->-->Exploring the Relationships Between Reporting Testing Positive for COVID-19 and Cannabis Use: an Exploratory Study.-->-->PLOS ONE

Dear Dr. Baena-Jiménez,

Please submit your revised manuscript by Nov 01 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:-->

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

We look forward to receiving your revised manuscript.

Kind regards,

David Adedia, Ph.D

Academic Editor

PLOS ONE

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Additional Editor Comments :

The authors should consider the following:

The Cronbach's alpha of 0.459, is too low. The recoding process should be checked to ensure the low value is not due to that. In addition, the authors should consider assessing the validity of the scale as well as improve its reliability. A low reliability defeats the findings.

When the prevalence is either far above or below 0.5, the logistic regression does not provide efficient results. The prevalences per the different times is low and complementary log-log model would have been better.

In Table 3, IC should be changed to CI

P valor should be written as p-value.

T-test o χ2 should be written properly.

The document should be proofread to correct grammatical and punctuation errors, especially where spaces are required.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.-->

Reviewer #1: All comments have been addressed

Reviewer #3: (No Response)

Reviewer #4: (No Response)

**********

-->2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->3. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: No

**********

-->4. Have the authors made all data underlying the findings in their manuscript fully available?

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->5. Is the manuscript presented in an intelligible fashion and written in standard English?

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->6. Review Comments to the Author

Reviewer #1: Reviewer Comments (Round 2):

Thank you for the revised version of the manuscript. The authors have addressed most of the points raised in the initial review, and I appreciate the effort made to improve the clarity and transparency of the study. The inclusion of the STROBE checklist, detailed age distribution, and clarification regarding consent procedures are all welcome additions.

However, two important concerns remain and need to be addressed before the manuscript is suitable for publication:

Causal Language in the Conclusion and Interpretation of Results:

1.Despite the authors’ efforts to replace terms such as "association" with "estimate" or "correlation" in some parts of the manuscript, the conclusion still uses language that implies causality, which is not appropriate for a cross-sectional observational study. For instance, the statement:

“COVID-19 testing positive was associated with cannabis use, particularly last month consumption. It was also associated with increased academic performance, a higher number of isolations, and the perception that cannabis consumption worsens COVID-19.”

should be revised to avoid causal implications. This phrasing suggests a level of certainty and directionality that the study design does not support. I recommend using more cautious language such as: “An estimated association was observed between…” or “Data showed a correlation between…”

2.Introduction – Misleading Interpretation of the Literature:

The manuscript references the following article to support the claim that cannabis use directly increases the risk of acquiring COVID-19 (pag 3)

Griffith, N. B., Baker, T. B., Heiden, B. T., Smock, N., Pham, G., Chen, J., ... & Chen, L. S. Cannabis, Tobacco Use, and COVID-19 Outcomes. JAMA Network Open 7.6 (2024): e2417977-e2417977.

However, this cited study supports the broad assertion that “cannabis use was associated with an increased risk of hospitalization and ICU admission.” The authors of the cited study provide a more nuanced interpretation of the data, and this should be accurately reflected in the manuscript. Please revise this sentence to ensure it is a faithful representation of the original source, and avoid overstating the evidence. A more precise and referenced summary of the findings from Griffith et al. should be included.

Overall, the manuscript has improved significantly, and I thank the authors for their thoughtful revisions. I encourage them to address the remaining issues to ensure the manuscript reflects the study’s methodological limitations and the referenced literature with appropriate caution.

Reviewer #3: I have carefully reviewed this manuscript and below is my decision.

The paper is well-suited for publication in the Plos One. All comments are well-improved the quality of paper. Good luck!

Reviewer #4: The authors sought to explore the relationship between cannabis use and COVID-19 test results, adjusting for behavioural, psychological and sociodemographic variables. They basically utilized a cross-sectional sampling methodology with validated instruments to assess the key variables.

Cannabis use was defined based on recency into lifetime use, last year or last month and the authors used chi square and logistic regressions to explore the relationship.

In short, to address the hypothesis tables 2 and 3 are necessary but table 1 is unnecessary. For table 3 more details on the model-building strategies are needed and perhaps for each classification of cannabis use the authors may wish to present a parsimonious model. Another consideration that the authors could explore is dividing cannabis use into mutually exclusive groups of no use =669, last month 156 and some use more than a month ago (226) and use multinominal logistic regression. Additionally, the 95% CI for the Odds ratio would be a more useful statistic to include in Table 3.

The introduction and discussion covers the salient points.

**********

-->7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.-->

Reviewer #1: Yes:Cláudio Calixto Carlos da Silva

Reviewer #3: No

Reviewer #4: Yes:Marvin Reid

**********

PLoS One. 2026 May 7;21(5):e0347098. doi: 10.1371/journal.pone.0347098.r004

Author response to Decision Letter 2

21 Oct 2025

REVIEWER 1

We sincerely thank Reviewer #1 for their thoughtful and constructive feedback on the revised version of our manuscript. We appreciate the positive remarks regarding the improvements made, including the inclusion of the STROBE checklist, detailed age distribution, and clarification of the consent procedures. Below, we address each of the remaining concerns point by point.

1. Causal Language in the Conclusion and Interpretation of Results

Reviewer’s comment:

The reviewer correctly notes that some statements in the conclusion still imply causality, which is not appropriate for a cross-sectional design. The reviewer suggests using more cautious phrasing such as “An estimated association was observed between…” or “Data showed a correlation between…”.

Response:

We fully agree with the reviewer’s observation and have revised the relevant sections of the manuscript to ensure that all interpretations are expressed in non-causal terms. Specifically, the statement in the conclusion now reads:

“An estimated association was observed between COVID-19 positivity and cannabis use, particularly last-month consumption. Data also showed correlations with higher academic performance, a greater number of isolations, and the perception that cannabis consumption worsens COVID-19 outcomes.”

We have carefully reviewed the entire manuscript to ensure consistent use of language that accurately reflects the cross-sectional nature of the study and avoids any implication of causality.

2. Introduction – Misleading Interpretation of the Literature

Reviewer’s comment:

The reviewer points out that our citation of Griffith et al. (2024) could be interpreted as overstating the evidence, as the cited study reports associations with hospitalization and ICU admission rather than directly with infection risk.

Response:

We thank the reviewer for this valuable clarification. We have revised the text in the introduction to more accurately reflect the findings of Griffith et al. (2024). The revised sentence now reads:

“Previous studies, such as that by Griffith et al. (2024), have reported that cannabis use was associated with an increased risk of hospitalization and ICU admission among individuals with COVID-19.”

We believe this modification provides a more faithful representation of the original study and avoids overstating its conclusions. The corresponding reference has been retained and properly contextualized within our discussion.

REVIEWER 3

We really appreciate the comments of the reviewer.

REVIEWER 4

We sincerely thank Reviewer #4 for their helpful and constructive feedback, which has guided further refinement of our statistical analysis and presentation.

Comment:

The reviewer suggests providing more details on the model-building strategies used for Table 3, considering parsimonious models for each cannabis use category, exploring mutually exclusive cannabis-use groups with multinomial logistic regression, and including 95% confidence intervals for the odds ratios.

Response:

We appreciate these valuable suggestions:

1. Model-Building Strategy and Parsimonious Models and Cannabis Use Categories:

We appreciate your suggestion; however, this was not the objective of our study. Our aim was not to identify the most parsimonious model, but rather to conduct an exploration analysis by retaining all variables in order to examine whether any associations existed. Nevertheless, we have included in the limitation section that in future studies that consideration should be taking into account. It is reflected as follows:

“They also could consider reclassifying participants into mutually exclusive groups (no use = 669; last-month use = 156; use more than one month ago = 226) and conducting supplementary multinomial logistic regression analyses.”

2. 95% Confidence Intervals:

We have revised Table 3 and the 95% confidence intervals has been already included for all reported odds ratios, as suggested. We agree that this addition substantially enhances the interpretability and statistical transparency of the results.

We thank the reviewer for these insightful recommendations, which have strengthened both the methodological rigor and clarity of our results.

Attachment

Submitted filename: Answer_round2_Plsone.docx

pone.0347098.s003.docx^{(16.7KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0347098.r005

Decision Letter 2

Magdalena Szaflarski

29 Jan 2026

-->PONE-D-24-49229R2-->-->Exploring the Relationships Between Reporting Testing Positive for COVID-19 and Cannabis Use: an Exploratory Study.-->-->PLOS One

Dear Dr. Baena-Jiménez,

The authors did an admirable job addressing a slate of critiques from multiple reviewers over two rounds of reviews. However, there are a few gaps that remain, as pointed out by Reviewer 2. It is unfortunate that this reviewer did not get a chance to comment on the first revision, but after their careful assessment of Revision 2, the critiques listed in their current review are valid and need addressing. I understand, as Reviewer 2 does, potential frustration that this additional round of reviews may bring. However, I also agree with Reviewer 2 that with these few remaining adjustments, the paper will be publishable and high-quality. Along with Reviewer 2, I apologize for the extended review process. I look forward to receiving your final round of revisions.

Please submit your revised manuscript by Mar 15 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:-->

A letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

We look forward to receiving your revised manuscript.

Kind regards,

Magdalena Szaflarski, PhD

Academic Editor

PLOS One

Journal Requirements:

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

Reviewer #3: All comments have been addressed

**********

-->2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Yes

**********

-->3. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

Reviewer #2: N/A

Reviewer #3: Yes

**********

-->4. Have the authors made all data underlying the findings in their manuscript fully available?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

-->5. Is the manuscript presented in an intelligible fashion and written in standard English?

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

**********

-->6. Review Comments to the Author

Reviewer #1: I would like to thank the authors for the substantial improvements made throughout the revision process. The manuscript is now clearer, more consistent, and the main concerns raised in previous rounds have been adequately addressed. The adjustments to causal language, clarification of the introduction, and revisions throughout the text have strengthened the overall quality of the work.

At this point, I believe the manuscript is suitable for publication pending only minor formatting adjustments. Several tables still present formatting inconsistencies, including:

Table 1 appearing split across two pages;

Placeholder text such as “insertheretable1”, “insertheretable2”, and “ insertheretable3” remaining in the manuscript.

I kindly recommend a final formatting check to ensure that all tables appear as single, complete blocks and that placeholders are removed. These adjustments are minor and do not affect the scientific content of the manuscript.

Reviewer #2: I thank the authors for their work and for their involvement in the review process. I also take the opportunity to wish them all an happy new year.

I note the authors have "carefully reviewed the entire manuscript to ensure consistent use of language that accurately reflects the cross-sectional nature of the study and avoids any implication of causality." While this should not have required two rounds of peer-review, it is indeed finally appropriate in the body of the manuscript; it is, however not, in the Abstract. My review focuses therefore on the Abstract, as well as the introduction.

An outstanding element that deserve address is the apparent deterritorialisation of the results, which does not seem justified. This study was conducted in four specific urban contexts of Western Andalucía, and among adolescents. None of these elements are present in the title (geographical location [Andalucia], type of environment [urban], population studied [scholarised adolescents]). It is critical that these elements appear in the title, and clearly articulated in the abstract.

The importance of accurately representing the specificities of the localised regional context within which the study was conducted (urban context in Western Andalucía) is key.

I also stress that the territory in question (four specific large cities in Western Andalucía) is located at the najor entry point of cannabis resin for illicit markets, fromNorthern Africa to Europe. This absolutely unique situation is nowhere mentioned. Other geographical, socio-cultural, and political contextual elements may have been welcome.

Furthermore, I note that imported cannabis drugs from that Northern African region often constitute “hashish” (cannabis resin) and not “flowers” (dry herbal tops) which are the subject of most published research. Besides possible differences in effects on individual and public health, the consumption of hashish is, I believe, directly associated with that of tobacco. I may have missed it, but this critical element was not mentioned in the manuscript. Finally, there may be specific rituals of collective use and sharing associated with “hashish” that are not with “flowers”.

Tobacco consumption, type of product, use rituals, excess quantity on the market due to the major EU zone of transit… PLOS One has an international audience, not expected to be aware of these elements, and which should therefore be mentioned.

TITLE

I suggest deletion of initial "the" in the title, as in "Exploring Relationships Between".

I also respectfully propose to add language along the lines of: "among 89 Adolescents in Andalusian Cities." at the end.

I have the memory of an original title being perhaps more specific in that regard (but I could not locate it on the editorial manager).

ABSTRACT — Methods

"This study conducted in Andalusia, Spain, surveyed 1,051 adolescents aged 14 to 18 years, of whom 89 reported testing positive for COVID-19."

I continue to believe that the mention of the figure 1,051 is not relevant in the abstract —no more than the totla figure of adolescents in Westedn Andalucia. This is an article about positive results from a study of 89 participants. The abstract must reflect this in a non-misleading way. Given that the rest of the article refers to "our sample" without making clear that sample is 89, not 1,051.

The figure 1,051 is superfluous.

ABSTRACT — Results

"Sharing cannabis during the pandemic and the lack of perception that cannabis use exacerbates COVID-19 are related to cannabis use"

Did the authors intended to mean "is related to cannabis use" (or "related to…") instead of "are"? If so, the meaning changes drastically.

If not, the authors are saying with this sentence:

1) Sharing cannabis during the pandemic … is related to cannabis use — a wholly tautological statement.

2) lack of perception that cannabis use exacerbates COVID-19 … is related to cannabis use — a proper finding.

(1) is superfluous. The fact that (1) is merged with the entirely different (2) is concerning.

ABSTRACT — Conclusions

This section also requires considerable revision and restraint. Particularly, the latter sentence is perhaps superfluous or overstated. This paper does not in any way bring "comprehensive" knoelwedge, just additional elements. I must again note a regrettable tendency towards overstatement throughout.

These are signaling a certain lack of ability to communicate results in an accurate and transparent manner. Abstracts are critical parts of the research. I reiterate my call for a comprehensive rewriting of the abstract and title, keeping in mind modesty and the scope of these results: this is a study of 89 cases in 4 large cities in half of one region of Spain. It is an extremely insightful, interesting, well-conducted, and useful study. But it is not what it is not, and must focus on what it is.

INTRODUCTION §1

This opening is structurally problematic. It starts by talking about the WHO’s opinion on “the pandemic” without having qualified it prior.

In my opinion, this introduction ought to start with the first sentence from the M&M section (i.e., “In March 2020, a lockdown…” up to “… of our adolescents”), followed by the present sentence about WHO and end of pandemic period.

This would be a serious, solid, clear way to begin the article, and would allow to avoid subsequent repetitions (hence reducing the length of the introduction andM&M section).

INTRODUCTION §2

"The global increase in drug seizures in 2020 intensified during the coronavirus disease (COVID-19) pandemic in many countries [5]. In fact, the United Nations' Annual Report for 2020 against drug abuse highlighted that most countries reported an increase in cannabis consumption during the COVID-19 pandemic [6]."

Seizures are only reflective of one thing: police zeal and activity. Stop funding police, seizures go down: does that mean drug use goes down? It is inappropriate to conflate such distinct data in this sentence. Delete the paragraph, for global seizure data serve no analytical purpose. The only use of seizure data may be to address the hashish-contet mentioned elsewhere (but I assume this would not go in §2). Otherwise, this sentence and its discussion of global police activity has no room in a paper about adolescents in four specific urban contexts of Western Andalucía.

Provided that this entire paragraph adds nothing to the topic, and conflates broad data, I do not see any better solution than deleting it.

INTRODUCTION §3

"Cannabis consumption poses a threat to public health, since it stands as the most widely used illicit drug among teenagers globally [7]."

Prevalence alone does not constitute evidence of a “public health threat.” UNODC World Drug Report, the source cited, explicitly distinguishes between prevalence of use and of cannabis use disorders. Cannabis use disorders represent a subset of cannabis consumption. Failing to acknowledge this distinction, which is explicit in the cited source, while conflating widespread use with public health harm, is conceptually incorrect and misleading.

I would like to highlight that this seems to constitute a persistent trend in conflating prevalence, harm, simple use and use disorder, and causality — which apparently remain uncorrected despite repeated and explicit reviewer feedback across multiple rounds of review.

From a broader perspective, this paragraph does not serve the stated aims of the manuscript. The article does not examine cannabis use as a public health risk per se, but rather the association between cannabis use and reporting testing positive for COVID-19. As such, general statements about cannabis as a public health threat unrelated to COVID-19 (or possibly other similar infectious and/or lung-related health conditions) are not analytically relevant in this context.

The paragraph would be better aligned with the study objectives if it focused directly on prior evidence linking cannabis use and COVID-19 outcomes, followed by relevant prevalence data to contextualize the population studied (global → European → Spanish adolescents):

(sentence 1 of the new §) Previous studies, such as that by Griffith et al. (2024), have reported that cannabis use was associated with an increased risk of hospitalization and ICU admission among individuals with COVID-19. (sentence 2 of the new §) The global prevalence of cannabis use in the last year was 5.8% (corresponding to 12 million) among 15- and 16-year-old adolescents [8], with the highest prevalence worldwide observed in European youths aged 15 to 24 [6,9] (sentence 3 of the new §) move on with data about Spain’s consumption patterns among the youth, currently in the next paragraph (4th)

INTRODUCTION §4

Suggested merger with revised §3 as proposed above.

This does not apply to the final part of the paragraph: “the EDADES study (population aged 15 to 64) indicates an increasing trend from the age of 24 onwards”. If this article is about adolescents under 24, there are little reasons to mention this datum.

M&M

This section ought to refer to the specificities of the territory (4 large cities) and the product (resin mixed with tobacco, imports, large market), as mentioned above.

CONCLUSION.

"The findings of this exploratory study give light to possible interventions to reduce the harm of cannabis use in a pandemic situation"

Replace "the harm of cannabis" by "harms associated with cannabis use" you may want to add elements of context. This paper offers limited guidance on reducing the harms of pure flowers vaporised in, say, Hawaii. It serves for tobacco-hashcish mix in adolescents in Europe.

I would not recommend accepting a final version which would retain the mention of "interventions" as it currently stands. This article gives absolutely no insight for practical intervention. Stating so is a large leap. A premature one. It would be concerning if real-world public health interventions were based solely on such cross-sectional studies of small samples of urban adolescents.

Consider something along the lines of: "The findings of this exploratory study provide additional data in relation to the harms associated with the use of cannabis resin among adolescents, in this specific context, in a situation of public health emergency like the COVID-19 pandemic, and may provide insight in the design of public health interventions."

I am conscious of the discomfort this long review process may have caused to the authors, but I am confident that integrating these improvements will make for a paper reduced in its scope, but dramatically increased in its quality — which will benefit both public health and the authors' track record.

I thank you and am confident the authors' revised version will be good for publication.

Reviewer #3: I am happy having the opportunity to read and review the manuscript assigned to me, titled “Exploring the Relationships Between Reporting Testing Positive for COVID-19 and Cannabis Use: an Exploratory Study” submitted to Plos One.

I have carefully reviewed this manuscript and below is my decision.

The paper is well-suited for publication in the Plos One. All comments are well-improved the quality of paper. Good luck!

**********

-->7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.-->

Reviewer #1: Yes:Cláudio Calixto Carlos da Silva

Reviewer #2: No

Reviewer #3: No

**********

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PLoS One. 2026 May 7;21(5):e0347098. doi: 10.1371/journal.pone.0347098.r006

Author response to Decision Letter 3

16 Mar 2026

Please, find all of this information in the uploaded document titled "response to reviewers" for an easier review.

Reviewer #1:

I would like to thank the authors for the substantial improvements made throughout the revision process. The manuscript is now clearer, more consistent, and the main concerns raised in previous rounds have been adequately addressed. The adjustments to causal language, clarification of the introduction, and revisions throughout the text have strengthened the overall quality of the work.

At this point, I believe the manuscript is suitable for publication pending only minor formatting adjustments. Several tables still present formatting inconsistencies, including:

Table 1 appearing split across two pages;

Placeholder text such as “insertheretable1”, “insertheretable2”, and “ insertheretable3” remaining in the manuscript.

Response from authors:

We thank reviewer 1 for their comments. We have removed the 'insert Table 1 here' in all of the table’s placeholder, and Table 1 now appears on a single page.

Reviewer #2:

I thank the authors for their work and for their involvement in the review process. I also take the opportunity to wish them all an happy new year.

The importance of accurately representing the specificities of the localised regional context within which the study was conducted (urban context in Western Andalucía) is key.

TITLE

I suggest deletion of initial "the" in the title, as in "Exploring Relationships Between".

I also respectfully propose to add language along the lines of: "among 89 Adolescents in Andalusian Cities." at the end.

I have the memory of an original title being perhaps more specific in that regard (but I could not locate it on the editorial manager).

ABSTRACT — Methods

"This study conducted in Andalusia, Spain, surveyed 1,051 adolescents aged 14 to 18 years, of whom 89 reported testing positive for COVID-19."

The figure 1,051 is superfluous.

ABSTRACT — Results

"Sharing cannabis during the pandemic and the lack of perception that cannabis use exacerbates COVID-19 are related to cannabis use"

Did the authors intended to mean "is related to cannabis use" (or "related to…") instead of "are"? If so, the meaning changes drastically.

If not, the authors are saying with this sentence:

1) Sharing cannabis during the pandemic … is related to cannabis use — a wholly tautological statement.

2) lack of perception that cannabis use exacerbates COVID-19 … is related to cannabis use — a proper finding.

(1) is superfluous. The fact that (1) is merged with the entirely different (2) is concerning.

ABSTRACT — Conclusions

INTRODUCTION §1

This opening is structurally problematic. It starts by talking about the WHO’s opinion on “the pandemic” without having qualified it prior.

This would be a serious, solid, clear way to begin the article, and would allow to avoid subsequent repetitions (hence reducing the length of the introduction andM&M section).

INTRODUCTION §2

Provided that this entire paragraph adds nothing to the topic, and conflates broad data, I do not see any better solution than deleting it.

INTRODUCTION §3

"Cannabis consumption poses a threat to public health, since it stands as the most widely used illicit drug among teenagers globally [7]."

INTRODUCTION §4

Suggested merger with revised §3 as proposed above.

M&M

This section ought to refer to the specificities of the territory (4 large cities) and the product (resin mixed with tobacco, imports, large market), as mentioned above.

CONCLUSION.

"The findings of this exploratory study give light to possible interventions to reduce the harm of cannabis use in a pandemic situation"

I thank you and am confident the authors' revised version will be good for publication.

Response from authors:

We sincerely thank the reviewer for the careful, detailed, and constructive feedback. We appreciate the emphasis on contextual precision, conceptual clarity, and restraint in interpretation. Below we respond point by point and indicate how the manuscript has been revised accordingly.

1. Title

We have:

• Removed the initial “The” as suggested.

• Revised the title to better reflect the specific population and scope.

• Included clarification regarding the study sample.

The new title reads: Association Between Reporting Testing Positive for COVID-19 and Cannabis Use Among Adolescents in Andalusia: an Exploratory Study

2. Abstract

Methods (Sample Size)

We appreciate the concern regarding potential ambiguity.

To improve clarity and avoid any perception of misleading framing:

• In the method section of the abstract states that the analyses focus on the 89 adolescents who reported testing positive.

• The total surveyed population (1,051) is no longer foregrounded in a way that could obscure the analytical sample.

• The wording has been revised to ensure that “our sample” consistently refers to the 89 participants analyzed.

Results (Grammar and Tautology)

Thank you for highlighting this issue. The sentence has been rewritten to avoid ambiguity and tautology. We have removed the phrasing that could be interpreted as circular.

The revised sentence now states:

Individuals testing positive for COVID-19 are almost 2.89 times more likely to have used cannabis in the last month. Sharing cannabis among adolescents during the pandemic may increase the risk of COVID-19 transmission. Additionally, lack of perceived risk that cannabis use could exacerbate COVID-19 was associated with cannabis use during the pandemic.

Conclusions (Overstatement)

We agree that the previous wording overstated the contribution.

The conclusion has been substantially rewritten to reflect:

• The exploratory and cross-sectional nature of the study

• The limited sample size

• The contextual specificity

Any reference to “comprehensive knowledge” has been removed. The conclusions are now framed as providing additional contextualized evidence rather than broad claims.

It is reflected as follows:

Informing whether adolescents who use cannabis may be more likely to test positive for COVID-19 contributes to a better understanding of substance use patterns during a public health emergency. Given the exploratory and cross-sectional nature of this study, as well as its limited and context-specific sample, the findings should be interpreted with caution. The results offer additional contextualized evidence that may help inform future research on the relationship between COVID-19-related factors and cannabis use among adolescents in Western Andalusia.

3. Introduction — Structure (§1)

We agree with the structural suggestion.

The Introduction has been reorganized so that:

• The contextual description of lockdown in March 2020 now appears at the beginning.

• The WHO declaration is introduced after situating the timeline.

• Redundancies between Introduction and Methods have been eliminated.

This restructuring has improved clarity and reduced repetition.

Introduction — Drug Seizure Data (§2)

We accept the reviewer’s concern regarding the interpretative limitations of seizure data.

The paragraph referencing global seizure trends has been removed, as it did not directly serve the analytical aims of the manuscript.

Introduction — Public Health Threat and Conceptual Distinctions (§3)

We appreciate this important conceptual clarification.

The paragraph has been revised to:

• Avoid conflating prevalence with harm or use disorder.

• Remove generalized statements framing cannabis use as inherently a “public health threat.”

• Focus directly on prior evidence linking cannabis use with COVID-19 outcomes.

• Present prevalence data in a structured progression, as suggested.

We agree that this revision better aligns the Introduction with the study objective.

EDADES Data Reference

We have removed the reference to trends in populations aged 24+ years, as it was not directly relevant to an adolescent sample.

Contex

Attachment

Submitted filename: Response to Reviewers_3rdRound_mls.docx

pone.0347098.s004.docx^{(30.9KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0347098.r007

Decision Letter 3

Vincenzo De Luca

30 Mar 2026

Association Between Cannabis Use and Result of COVID-19 Testing Among Scholarised Adolescents in Andalusia: a Cross-Sectional Study

PONE-D-24-49229R3

Dear Dr. Baena-Jiménez,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Academic Editor

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Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

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Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #2: Yes

Reviewer #3: Yes

**********

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Reviewer #2: Yes

Reviewer #3: Yes

**********

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

-->6. Review Comments to the Author

Reviewer #1: I would like to thank the authors for their careful revisions and for adequately addressing all comments raised in the previous review round. The manuscript has improved substantially in clarity, consistency, and overall presentation.

The previously noted formatting issues have been corrected, including the proper placement of tables and removal of placeholder text. These adjustments resolve the remaining concerns.

At this stage, I have no further comments. I consider the manuscript scientifically sound, well presented, and fully suitable for publication in its current form.

Reviewer #2: Thank you.

Reviewer #3: I am happy having the opportunity to read and review the manuscript assigned to me, titled “Association Between Cannabis Use and Result of COVID-19 Testing Among Scholarised Adolescents in Andalusia: a Cross-Sectional Study” submitted to Plos One.

I have carefully reviewed this manuscript and below is my decision.

The paper is well-suited for publication in the Plos One. All comments are well-improved the quality of paper. Good luck!

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Reviewer #1: Yes:Cláudio Calixto Carlos da Silca

Reviewer #2: No

Reviewer #3: No

**********

PLoS One. doi: 10.1371/journal.pone.0347098.r008

Acceptance letter

Vincenzo De Luca

PONE-D-24-49229R3

PLOS One

Dear Dr. Baena-Jiménez,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Attachment

Submitted filename: Answer to reviewer 2.docx

pone.0347098.s002.docx^{(49.3KB, docx)}

Attachment

Submitted filename: Answer_round2_Plsone.docx

pone.0347098.s003.docx^{(16.7KB, docx)}

Attachment

Submitted filename: Response to Reviewers_3rdRound_mls.docx

pone.0347098.s004.docx^{(30.9KB, docx)}

Data Availability Statement

The data underlying the results presented in the study are available from Zenodo (a public repository; accession DOI: https://doi.org/10.5281/zenodo.15106665).

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PERMALINK

Association between cannabis use and result of COVID-19 testing among scholarised adolescents in Andalusia: A cross-sectional study

María-Carmen Torrejón-Guirado

Miguel Ángel Baena-Jiménez

Marta Lima-Serrano

Roles

Abstract

Aims

Methods

Results

Conclusions

Introduction

The study

Materials and methods

Design and population

Fig 1. Recruitment Process Flowchart Based on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement [18].

Measurements

Testing COVID-19.

Cannabis consumption.

Sociodemographic and psychological variables.

Behavioural variables.

Perception variables associating COVID-19 with cannabis use.

Procedure

Participants consent and ethics statement

Statistical analyses

Results

Study sample characteristics and COVID-19 testing positive

Table 1. Sociodemographic, psychological, and related COVID-19 and cannabis behaviour and perception description of the sample and its correlation with adolescents’ COVID-19 testing positive.

Cannabis use and estimated factors

Table 2. Sociodemographic, Psychological, and COVID-19 Variables Related to Cannabis Use in Adolescents.

Relationship of COVID-19 testing positive and Cannabis Use

Table 3. Resultant Variables in Logistic Regression Analysis for Cannabis Consumption on Adolescents.

Discussion

Strengths and limitations

Conclusion

Data Availability

Funding Statement

References

Decision Letter 0

Aman Goyal

Roles

Author response to Decision Letter 1

Decision Letter 1

David Adedia

Roles

Author response to Decision Letter 2

Decision Letter 2

Magdalena Szaflarski

Roles

Author response to Decision Letter 3

Decision Letter 3

Vincenzo De Luca

Roles

Acceptance letter

Vincenzo De Luca

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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