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. Author manuscript; available in PMC: 2023 Mar 1.
Published in final edited form as: Early Interv Psychiatry. 2021 May 3;16(3):264–271. doi: 10.1111/eip.13153

Cannabis use, self-perceived risk, perceived peer approval and parental attitudes among youth at clinical high-risk for psychosis

Ivanka Ristanovic 1, Katherine S F Damme 1, Jordan E DeVylder 2, Jason Schiffman 3, Vijay A Mittal 1,4,5,6
PMCID: PMC9940656  NIHMSID: NIHMS1873614  PMID: 33942529

Abstract

Aim:

Cannabis use is associated with greater likelihood of psychosis. The relationship between attitudes about cannabis and use has not been examined in youth at clinical high-risk (CHR) for psychosis. Additionally, the shifting legal landscape can provide a valuable context for evaluating use and related attitudes.

Methods:

This study included 174 participants (44 CHR, 43 healthy control [HC] youth-parent dyads). Youth completed measures of self-reported cannabis use confirmed with a urinalysis, self-perceived risk and perceived peer attitudes. Parents reported attitudes about youth use. Legalization occurred halfway during a 5-year study in Colorado, providing an opportunity to cross-sectionally examine its role in use and attitudes.

Results:

Frequency of youth reporting cannabis use was significantly higher in CHR (69%) than control group (30%). Use in CHR group was associated with higher perceived peer approval (r = .57), increased parental permissiveness (r = .28) and lower self-perceived risk (r = −.26). Comparing samples participating pre and post-legalization, use remained stable within each group. Group differences in parental permissiveness shifted; trend toward decrease in permissiveness in CHR group (η2partial = .07) and a significant increase in HCs (η2partial = .16) were observed. Post-legalization, use in CHR group correlated with higher perceived peer approval (r = .64), lower self-perceived risk (r = −.51) and higher parental permissiveness (r = .35, trend).

Conclusions:

Taken together, results indicate a relationship between self and peer/parental attitudes about cannabis and use in youth at CHR for psychosis. These factors are important to consider within the legalization context given the changes in parental attitudes and a stronger association between use and attitudes in this group post-legalization.

Keywords: attitudes, cannabis, clinical high-risk for psychosis, legalization

1 |. INTRODUCTION

Cannabis is one of the most widely used drugs in the United States, with use rates rising over the last two decades (Carney, Cotter, et al., 2017; Wisk et al., 2019). A national survey conducted by the Substance Abuse and Mental Health Services Administration (SAMHSA) showed a sizable increase in cannabis use between 2002 (11%) and 2018 (15.9%), most notably in young adults (Substance Abuse and Mental Health Services Administration, 2019). In addition to growing use, laws and policies pertaining to legalization of cannabis for medicinal and recreational use are changing rapidly. Yet, it is currently unclear if these law changes lead to changes in use trends, attitudes toward cannabis and the relationship between the two. The impact of these laws on use should be critically examined in psychosis-risk populations. Cannabis use in individuals meeting criteria for clinical high-risk (CHR) syndrome for psychosis is higher compared with the general population (Carney, Yung, et al., 2017) and is a prominent risk factor associated with exacerbation of attenuated psychotic symptoms (Corcoran et al., 2008; Di Forti et al., 2019; Valmaggia et al., 2014). Existing literature suggests the possibility that reducing cannabis use among individuals at CHR may be a viable treatment target to mitigate psychosis onset (Marconi et al., 2016).

One possible intervention target for cannabis use is attitudes toward its harmfulness (Evers et al., 2020). In typically developing youth, decreases in risk perception are associated with increases in use prevalence (Compton et al., 2016; Pacek et al., 2015). Further, social norms are associated with odds of use (Evers et al., 2020; Wu et al., 2015). For example, perceived and actual peer use is a significant predictor of use initiation and persistence (Chabrol et al., 2006; Neighbors et al., 2008; Piontek et al., 2013), while odds of use decrease when friends disapprove of it (Palamar et al., 2014). Additionally, in typically developing adolescents and young adults, permissive parental attitudes have been linked to cannabis use (Bailey et al., 2016; Kerr et al., 2015; Napper, Froidevaux, & LaBrie, 2016). Although investigations linking these attitudes and cannabis use in youth at CHR for psychosis are lacking, one study indicated that social motives are one of the most common reasons for use (Gill et al., 2015). Therefore, further examining the relationship between peer and parental attitudes and use in this population is critical.

Cannabis use and impact of attitudes are also important to examine within the context of shifting cannabis laws. This is particularly relevant given the observed trends of lower prices, easier access to and higher potency of cannabis following legalization (Murray & Hall, 2020). In fact, a growing concern has been that cannabis legalization may increase youth use (Lynne-Landsman et al., 2013). Moreover, among adolescents, perceived risk significantly declined over the last several years (Johnston et al., 2019), and emerging research suggests that cannabis decriminalization and commercialization relate to these shifting perceptions (Hasin, 2018; Schuermeyer et al., 2014). In terms of parental perceptions, despite a decrease in perceived harm following legalization, parents remain largely opposed to adolescent use (Eisenberg et al., 2019; Jones et al., 2020; Kosterman et al., 2016; Lamb & Crano, 2014). In light of these attitude and possible use changes, identifying contributing risk and protective factors could help mitigate effects of legalization on use.

In the current investigation, the first aim was to examine differences in cannabis use between youth at CHR for psychosis and matched healthy controls (HCs). It was predicted that the frequency of youth endorsing cannabis use would be higher in the CHR group. In the second aim, the relationship between youth use and attitudes was evaluated in each group. It was predicted that self-perceived risk, perceived peer approval of use and permissive parental attitudes toward their children’s use would be associated with increased youth use in both groups. Lastly, cannabis legalization in Colorado (Colorado Constitution, n.d.) occurred half-way through the 5-year protocol, providing a unique opportunity to explore potential cross-sectional changes in cannabis use and related attitudes. In the first exploratory aim, group differences in cannabis use were examined pre-legalization and post-legalization. In the second exploratory aim, changes in attitudes between groups were examined relative to legalization. Finally, the relationship between youth use and attitudes in the CHR group was analysed pre-legalization and post-legalization.

2 |. METHODS

2.1 |. Participants

A total of 174 participants (87 youth-parent dyads) were recruited at the Adolescent Development and Preventive Treatment Program at the University of Colorado Boulder between August 2011 and July 2015. The sample included 44 CHR (19 females, 25 males, mean age = 18.34) and 43 HC (18 females, 25 males, mean age = 17.47) youth participants. Twenty-six dyads in each group completed study procedures pre-legalization of cannabis in Colorado and 18 CHR and 17 HC dyads post-legalization. Participants completed the procedures at one time-point (pre-legalization or post-legalization). Participants met criteria for psychosis-risk syndrome by one or more of the following: (a) presence of attenuated psychosis symptoms, (b) meeting schizotypal personality disorder criteria with global functioning decline and age <19 and (c) a family history of psychosis with global functioning decline. Exclusion criteria for all participants included ages <12 or >24, any psychotic disorder diagnosis and history of head injuries and neurological conditions. Additional exclusionary criteria for HC participants included meeting criteria for any psychosis-risk syndrome and family history of psychosis. The study was approved by the Institutional Review Board, and participants were consented/assented to all procedures. Strict confidentiality guidelines related to illicit drug use were explained to participants. Minors and their parents were informed that drug use will not be disclosed to parents.

2.2 |. Clinical interviews

Psychodiagnostics interviews were administered by trained assessors. The Structured Clinical Interview for Psychosis-Risk Syndromes (SIPS; McGlashan et al., 2010) was used to diagnose attenuated psychosis in CHR group and to rule out symptoms in HCs. The Structured Clinical Interview for DSM-IV (SCID; First et al., 2012) was administered to all youth participants to rule out psychosis and assess for other psychiatric disorders.

2.3 |. Youth cannabis use

Cannabis use in the last month was assessed using the Drug and Alcohol Use Scale (AUS/DUS; Drake et al., 1996). AUS/DUS is widely used in psychosis-spectrum populations (Woods et al., 2009), and it has high reliability (Brunette et al., 2006), good convergent validity (Wusthoff et al., 2011) and moderate concurrent validity (Moller & Linaker, 2010). A binary use/no use variable was used in all analyses. Additionally, in 73.6% of the sample, abstinence was confirmed with a urinalysis. All analyses were run with and without participants missing urine data. The direction and magnitude of the effects did not change, so the reported results are with the full sample. Four participants (3 CHR and 1 HC) reported no use, but urinalysis indicated presence of tetra-hydrocannabinol. They were excluded from all analyses.

2.4 |. Attitudes toward cannabis use

Youth attitudes were assessed using Medical Marijuana Questionnaire (Thurstone et al., 2011). The questions measured self-perceived risk related to regular cannabis use on a 5-point scale ranging from 1 (no risk) to 4 (great risk). Perceived peer approval was measured on a 3-point scale (1 = strongly disapprove, 2 = disapprove and 3 = would not disapprove). Parental attitudes were assessed on the same scale with two questions asking parents to indicate whether they object to cannabis use for medicinal and recreational purposes or if they hold more permissive views (see Data S1).

2.5 |. Statistical approach

Independent samples t-tests and chi-squares were utilized to test group differences in demographic variables. Chi-squares were used to examine group differences in cannabis use in the entire sample and pre-legalization and post-legalization. Univariate analyses of variance (ANOVAs) were used to evaluate the effects of group, legalization time-point and their interaction on self-perceived risk, perceived peer approval and parental attitudes. Point biserial correlations were employed to examine the relationship between self, perceived peer and parental attitudes with cannabis use in the CHR group pre-legalization and post-legalization. Results from predicted analyses (aims 1 and 2) are presented as one-tailed and from exploratory ones (aim 3) as two-tailed.

3 |. RESULTS

3.1 |. Sample characteristics

CHR and HC groups did not significantly differ on demographic characteristics including age (t[85] = 1.67, p = .09), sex (χ2[1, N = 87] = .02, p = .90), race (t[85] = 1.86, p = .07), ethnicity (χ2[1, N = 87] = .30, p = .58) and parental education (t[82] = .49, p = .62; Table 1). Additionally, pre-legalization and post-legalization samples were well matched on demographics (see Data S1).

TABLE 1.

Demographic characteristics by group

CHR HC p
Sex
 Males 25 25
 Females 19 18
 Total 44 43 NS
Age
 Mean years (SD) 18.34 (1.99) 17.47 (2.84) NS
Race* – n (%) NS
 East Asian --- 2 (4.7)
 Southeast Asian --- 1 (2.3)
 Black --- 1 (2.3)
 Central/South American 9 (20.5) 12 (27.9)
 White 33 (75) 26 (60.5)
 More than one race 1 (2.3) 1 (2.3)
Ethnicity – n (%)
 Hispanic 11 (25) 13 (30.2) NS
Parental education
 Mean years (SD) 16.12 (2.16) 15.85 (2.69) NS
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Note: CHR, clinical high-risk; HC, healthy controls; NS, not significant.

a

In some racial groups, there is no or limited representation; therefore, lack of racial differences should be interpreted with caution.

3.2 |. Youth cannabis use

In the CHR group the frequency of youth reporting cannabis use was higher (χ2[1, N = 87] = 5.89, p = .01) than in the HC group (Figure 1, Panel 1).

FIGURE 1.

FIGURE 1

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Percentages of youth cannabis use by group; Panel 1 represents use in the whole sample. Panel 2 represents use before and after legalization. *p < .05; CHR, clinical high-risk; HC, healthy controls; ns, not significant

3.3 |. The relationship between attitudes and youth use

Self-perceived risk was associated with cannabis use at trend-levels in the CHR group (r = −.26, p = .051) but not in HCs (r = .001, p = .50). Perceived peer approval was highly associated with use in both groups (CHR, r = .57, p < .001; HC, r = .52, p < .001). Permissive parental attitudes were significantly associated with more use in the CHR group (r = .28, p = .03) and at trend-level in HCs (r = .24, p = .06).

3.4 |. Pre-cannabis and post-cannabis legalization

3.4.1 |. Youth use

Pre-legalization, CHR and HC groups significantly differed in cannabis use (χ2[1, N = 52] = 5.44, p = .02). Post-legalization, the difference was not significant (χ2[1, N = 35] = .96, p = .33; Figure 1, Panel 2). However, use did not change in either group, though a non-significant decline was observed in the CHR group (χ2[1, N = 44] = .53, p = .47) and a non-significant increase in the HC group (χ2[1, N = 43] = .11, p = .73).

3.4.2 |. Attitudes toward cannabis use pre-legalization and post-legalization

No significant effects were observed for group (F[1,78] = .59, p = .44, η2partial = .008), legalization time-point (F[1,78] = .005, p = .94, η2partial = 0) or their interaction (F[1,78] = .003, p = .96, η2partial = 0) on self-perceived risk. Although groups differed on perceived peer approval (F[1,7] = 5.6, p = .004, η2partial = .1), there were no significant legalization (F[1,79] = .27, p = .6, η2partial = .003) or group by legalization interaction (F[1,79] = .47, p = .5, η2partial = .006) effects.

For parental permissiveness, univariate ANOVA revealed a significant main effect of group (F[1,83] = 6.55, p = .01, η2partial = .07), no effect of legalization time-point (F[1,83] = .07, p = .79, η2partial = .001) and a significant effect of their interaction (F[1,83] = 9.28, p = .003, η2partial = .1). Post-hoc ANOVAs revealed a striking shift in attitudes. Specifically, pre-legalization, parents in the CHR group were significantly more permissive than the HC parents (F[1,50] = 31.38, p < .0001, η2partial = .32), but the groups did not differ post-legalization (F[1,33] = .08, p = .78, η2partial = .001). Additionally, parents of CHR youth reported a trend-level decrease in permissiveness (F[1,42] = 3.01, p = .09, η2partial = .07) and parents of HC youth a significant increase (F[1,41] = 7.84, p = .008, η2partial = .16; Figure 2).

FIGURE 2.

FIGURE 2

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Parental attitudes by group before and after legalization. ^p = trend-level significance; *p < .05; **p < .0001; CHR, clinical high-risk; HC, healthy controls; ns, not significant; error bars represent the standard error of the mean

3.4.3 |. The relationship between attitudes and youth use relative to legalization in the clinical high-risk group

Self-perceived risk was not associated with cannabis use pre-legalization (r = −.12, p = .58); however, association was significant post-legalization (r = −.51, p = .04). Perceived peer approval was highly correlated with use both pre-legalization (r = .53, p = .007) and post-legalization (r = .64, p = .006). Permissive parental attitudes were not significantly associated with use pre-legalization (r = .20, p = .33); post-legalization, they were moderately correlated, but this relationship remained non-significant (r = .35, p = .16; Table 2).

TABLE2.

Correlations between cannabis use and attitudes in youth meeting criteria for CHR for psychosis syndrome

Before Legalization After Legalization
Self- Perceived Risk Perceived Peer Approval Permissive Parental Attitudes Self- Perceived Risk Perceived Peer Approval Permissive Parental Attitudes
Youth Use (r) −.11 .53** .2 −.51* .64** .35^
CHR HC
Self- Perceived Risk Perceived Peer Approval Permissive Parental Attitudes Self- Perceived Risk Perceived Peer Approval Permissive Parental Attitudes
Youth Use (r) −.26^ .57** .28* .001 .52** .24^
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Note:

^

p = trend-level significance;

*

p < .05;

**

p < .01.

4 |. DISCUSSION

The current study provided novel insights into the relationship between youth cannabis use and self-perception about associated risks as well as parental and peer influences. Additionally, exploratory analyses indicated cannabis legalization may be related to changes in parental attitudes and stronger association between attitudes and use in youth at risk for psychosis. First, the findings replicated a growing literature indicating that individuals meeting criteria for CHR syndrome report more cannabis use than HCs (Baker et al., 2010; Carney, Cotter, et al., 2017; Carney, Yung, et al., 2017). Elevated use is a particular concern for this population because it is associated with increased risk and higher transition rates to formal psychosis (Kraan et al., 2016; Marconi et al., 2016; Moore et al., 2007; Wall et al., 2016). Therefore, implementing early treatments targeting cannabis use reductions may be critical for improving clinical outcomes.

Attitudes toward cannabis use may be a promising intervention target considering youth use is impacted by social norms and perceptions about cannabis harmfulness (Compton et al., 2015; Evers et al., 2020; Wu et al., 2015). First, perceived peer approval appears particularly relevant as it was associated with use in both groups. This finding is consistent with literature suggesting that actual and perceived peer attitudes inform cannabis use (Chabrol et al., 2006; Neighbors et al., 2008; Piontek et al., 2013). Second, in line with the existing evidence (Kerr et al., 2015; Napper, Kenney, et al., 2016; Olsson et al., 2003; Voisine et al., 2008), the results suggest parental attitudes are associated with youth use in the CHR group and at a trend-level in HCs. Decreases in peer contact among individuals at CHR for psychosis could be contributing to higher reliance on parents. Indeed, this population presents with social functioning declines (Addington et al., 2008; Velthorst et al., 2018) and increased asociality (Piskulic et al., 2012). Although the correlational design did not conclusively indicate whether parental permissiveness relates to use over and above perceived peer approval, understanding parental factors could yield important insights into use related protective factors. Lastly, youth attitudes were not related to use in the HC group, but higher risk perception was associated with lower use at trend-levels in the CHR group. Although potential confounding factors could be contributing to these divergent associations, this finding may indicate that youth at CHR have insight into their symptoms and related risk factors. In fact, a recent meta-analysis suggested that cognitive insight in this population is intact (Donde et al., 2020), providing a promising target for risk prevention.

Additionally, use, attitudes and their relationship were explored in light of potential implications of changing cannabis laws. The presented findings should be interpreted with caution given the small sample size and the cross-sectional design of the study. In line with evidence from the general population (Wall et al., 2016), it appears that legalization may not be contributing to changes in use likelihood. It is possible that use does not increase rapidly because policy changes and establishing distribution systems typically lag after laws have been passed (Pacula et al., 2015). Further, as expected, CHR group reported significantly elevated use when compared with HCs pre-legalization. However, considering probability of use did not change in either group, it was surprising that the groups were not significantly different post-legalization. While non-significant use decreases in the CHR group and small increases in HCs were observed (Figure 1, Panel 2), the lack of significant difference between groups could be due to the smaller sample size post-legalization.

Attitudes about cannabis are a possible factor associated with use relative to legalization. Somewhat surprisingly, self-perceived risk did not differ between groups and did not change post-legalization. Changes in risk perception are more likely to occur in regular users (Andersson et al., 2009; Okaneku et al., 2015). Therefore, the lack of attitude changes could be explained by the lack of use changes. Further, CHR group reported higher perceived peer approval than HCs. However, consistently with previous findings (Blevins et al., 2018), it did not change post-legalization in either group. Most strikingly, parent permissiveness changed relative to legalization. In parents surveyed pre-legalization, those in the CHR group reported significantly more permissive attitudes toward their children’s use compared with the HC group; the attitudes were comparable between groups surveyed post-legalization. This shift reflected a trend-level permissiveness decrease in the CHR group and a significant increase in the HC group. In the absence of their children’s health problems, HC parents may be less concerned with risks associated with use (McGinty et al., 2017). Taken together, these findings suggest a complex relationship between cannabis legal status and attitudes.

The relationship between self-perceived risk and use differed between CHR samples recruited pre and post-legalization. Higher self-perceived risk was associated with lower use and vice versa only post-legalization. Interestingly, although risk perception remained stable, youth at CHR appeared to rely more on their attitudes to inform their use post-legalization. CHR youth may be becoming more aware of associations between risk and use considering reports of greater risk for psychosis related to higher potency of commercially available cannabis (Di Forti et al., 2014; Murray et al., 2016). Notably, given the cross-sectional design, cohort effects other than legalization could be contributing to this association. Next, the relationship between perceived peer approval and use did not change relative to legalization. However, the correlational analyses indicated that pre-legalization parental permissiveness and youth use were not related, but that lower permissiveness was associated with less use at trend-levels post-legalization. These findings could be partially explained by increased parenting involvement observed among parents of children with medical conditions (Ellis et al., 2008). In response to increasing objection to cannabis use, parents of youth at CHR could be becoming more involved with decision making related to use.

The current study presents with some limitations. First, the sample size was small. Second, correlational analyses did not account for multiple comparisons; therefore, the relationship between attitudes and cannabis use should be interpreted with caution. More powered investigations should utilize models directed at analysing whether each attitude type uniquely predicts cannabis use. Additionally, the current study did not capture means, dosage, duration and frequency of use. Future investigations should examine these factors in relation to attitudes. Exploratory analyses should be interpreted with caution. The cross-sectional design did not capture changes over time within an individual. The identified changes post-legalization could be due to potential confounding variable differences between samples recruited pre and post-legalization. Future work would benefit from utilizing longitudinal mixed models to examine within group changes. This approach would more directly assess the effects of cannabis legalization on use and attitudes and address potential issues of cohort effects in cross-sectional models. Lastly, future studies should examine links between symptoms and attitudes and whether their relationship informs cannabis use among CHR youth.

Supplementary Material

Supplementary Document

ACKNOWLEDGEMENTS

This work has been supported by the National Institutes of Mental Health (grant numbers R01MH094650 and R21/R33 Award, MH103231 [VAM]).

Funding information

National Institutes of Mental Health, Grant/Award Numbers: MH103231, R21/R33, R01MH094650

Footnotes

CONFLICT OF INTEREST

The authors declare no conflicts of interest.

SUPPORTING INFORMATION

Additional supporting information may be found online in the Supporting Information section at the end of this article.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

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Associated Data

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

Supplementary Materials

Supplementary Document
NIHMS1873614-supplement-Supplementary_Document.docx (14.2KB, docx)

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

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