Subjective Effects of Simultaneous Alcohol and Cannabis vs. Alcohol-Only Use in College Students: A Qualitative Analysis

Abstract

Objective:

Theoretical models of addictive behavior suggest that subjective effects serve as a mechanism through which substance use disorders develop. However, little is known about the subjective effects of simultaneous alcohol and cannabis use, particularly whether simultaneous use 1) heightens specific subjective effects or 2) is related to unique subjective effects relative to single substance effects. The current study used formative, qualitative data analysis to examine patterns of responses within open-answer text response data on subjective effects of simultaneous use.

Method:

College students who simultaneously use alcohol and cannabis (N=443; 68.2% female) were asked to describe how alcohol effects differ on simultaneous alcohol and cannabis use vs. alcohol-only use days.

Results:

Conventional Content Analysis revealed nine concepts related to simultaneous (vs. alcohol-only) use subjective effects including: (1) increased/decreased impairment, (2) low arousal/relaxation, (3) balancing/replacement effects, (4) “cross-faded” effects, (5) little-to-no differences, (6) altered sensation and perception, (7) increased negative affective states, (8) increased appetite, and (9) increased/decreased negative consequences. Increased impairment (N=191) and increased relaxation (N=110) were the most often endorsed subjective effects, followed by decreased impairment (N=55), balancing/replacement effects (N=50) and cross-faded/enhancement effects (N=44).

Conclusions:

Subjective effects from simultaneous use largely map onto domains of single-substance alcohol and cannabis effects (e.g., relaxation, sociability, cognitive/behavioral impairment), but also include distinct domains related to simultaneous use (e.g., balancing/replacement effects, altered sensation and perception). Future quantitative research is needed to validate measures of subjective effects from simultaneous use and their relations with use behavior.

Introduction

Heavy drinking and alcohol-related problems remain serious public health concerns, as they are common (Grant et al., 2017), costly (Sacks et al., 2015), and related to negative outcomes, including premature death and development of alcohol use disorder symptoms (e.g., CDC, 2018; Waddell et al., 2021a; Wechsler et al., 1994; 1995). Simultaneous alcohol and cannabis use, defined as using alcohol and cannabis so that their effects overlap (Gunn, Aston, & Metrik, 2022; Lee et al., 2022), is a consistent risk factor for heavier drinking and alcohol-related problems (e.g., Yurasek, Aston, & Metrik, 2017). Individuals who simultaneously use alcohol and cannabis report heavier drinking and more alcohol-related problems (Midanik et al., 2007; Patrick et al., 2018; Waddell & Marszalek, 2022), and simultaneous use days (compared to alcohol-only days) are associated with heavier drinking and acute negative consequences for individuals who simultaneously use alcohol and cannabis (e.g., Gunn et al., 2018; Lee et al., 2020; Metrik et al., 2018).

Although several studies have sought to test for whom simultaneous use (compared to alcohol-only) days are most risky (Daros et al., 2021; Metrik et al., 2018; Waddell et al., 2021b), little attention has been given to mechanisms through which simultaneous use confers acute risk for heavier drinking and negative consequences. One theoretically important mechanism is subjective effects from substance use. Subjective effects, defined as the combination of pharmacological and expectancy effects of substance use on mood and behavior, are strong predictors of heavier alcohol/cannabis consumption and related problems (e.g., Morean & Corbin, 2010; King et al., 2011; King et al., 2016; Metrik et al., 2012; Treloar-Padovano & Miranda, 2018; Waddell et al., 2020a). Theoretical models of addictive behavior suggest that an individual’s subjective experience/subjective effects represent a unique mechanism through which in-the-moment reward and/or relief reinforces problem substance use across time (Sher, 1991). However, little is known about subjective effects experienced from simultaneous alcohol and cannabis use, particularly a) whether certain subjective effects from alcohol or cannabis are enhanced by simultaneous use, or b) whether there are unique effects of simultaneous use relative to single-substance alcohol/cannabis use subjective effects.

Theory suggests that simultaneous alcohol and cannabis use may have additive and/or synergistic effects (e.g., Downey et al., 2013; Ramaekers et al., 2011). An additive effect would suggest that simultaneous use enhances single substance subjective effects, whereas a synergistic effect would suggest that simultaneous use has unique subjective effects compared to single substance use. Of the limited research on simultaneous use and subjective effects, most studies have found that simultaneous use is additive, in that simultaneous use is associated with greater intoxication levels as well as longer durations of impairment (e.g., Wickens et al., 2022; Lee et al., 2017; Patrick & Lee, 2018; Chait & Perry, 1994; Hartman et al., 2015; Sokolovsky et al., 2020). In controlled laboratory settings, studies have found that alcohol increases THC blood levels, results in greater “euphoria”, and results in longer lasting impairment (Lukas & Orozco, 2001; Hartman et al., 2015; Hartman et al., 2016). Using ecological momentary assessment, two studies found that simultaneous use was associated with feeling more “drunk” (Lipperman-Kreda et al., 2017) and more “intoxicated” (Sokolovsky et al., 2021). However, Linden-Carmichael et al. (2021) found that simultaneous use days did not differ in levels of “intoxication” from alcohol-only days. Finally, Lee et al. (2017) found that simultaneous days (retrospectively reported) were associated with feeling more “drunk”, “clumsy”, “confused” and “dizzy” (i.e., sedation; Martin et al., 1993) compared to alcohol-only days. Thus, it remains unclear precisely which subjective effects are present and/or enhanced on simultaneous use days. Furthermore, the studies reviewed have assessed subjective effects determined a priori to be important (e.g., “drunk”, items from the BAES; Martin et al., 1993) rather than asking participants in their own words what they experience due to simultaneous use.

Formative, qualitative work may be better suited to inform our understanding of subjective effects of simultaneous use. Qualitative methods have become particularly important in the field of alcohol misuse, and several studies using these methods have yielded important insights related to the context in which substance use is evaluated (e.g., Aston et al., 2019; Janssen et al., 2014; Merrill et al., 2018; Merrill et al., 2021). For instance, one study found that several alcohol consequences, that are considered by the research community to be “negative”, are not in fact perceived as “negative” – rather, contextual factors influence subjective evaluations of such negative consequences (e.g., Merrill et al., 2018). More recently, another study investigated (via qualitative interviews) participants’ motivation to simultaneously use alcohol and cannabis (Boyle et al., 2021), and found unique motivations for simultaneous use that are not present in the single-substance alcohol/cannabis literature (e.g., harm-reduction). Additional qualitative data analysis may prove useful in establishing which subjective effects are enhanced or exacerbated by simultaneous use based on textual data from participants.

Only one study to our knowledge has queried participants about subjective effects of simultaneous use. This study focused on anticipated effects (Waddell et al., 2022a), and exclusively used items from validated alcohol and cannabis expectancy measures. Thus, outside of validated single-substance measures and researcher-selected items (e.g., “drunk”, “intoxicated”, “euphoria”), little is known about how participants describe the subjective experience of simultaneous use. Further explicating these effects is important for theoretical models of simultaneous use (e.g., Risso et al., 2020; Subbaraman, 2016), as well as interventions that target an individual’s subjective experiences when using (e.g., Darkes & Goldman, 1994; Waddell et al., 2022b). Therefore, the current study sought to better understand patterns and language related to subjective effects of simultaneous alcohol and cannabis use compared to using alcohol-alone, particularly in college students. College students were selected as the primary population of interest because college student alcohol and cannabis co-use is common, on the rise, and associated with a variety of negative consequences (e.g., Gunn et al., 2018; Jackson et al., 2020; McCabe et al., 2021; White et al., 2019; Sokolovsky et al., 2021). Therefore, we used college student open-response textual data and Conventional Content Analysis (Hsieh & Shannon, 2005), to identify subjective effects of simultaneous use versus alcohol-only use. Qualitative analysis was approached within an exploratory lens, and no a priori concepts were established before reading and analyzing textual data.

Method

Participants

Participants (N=443) were college students who simultaneously used alcohol and cannabis recruited from a large southwestern university as part of a study on alcohol and cannabis expectancies (Waddell et al., 2022a). The parent study recruited a mix of participants who used alcohol-only and who simultaneously used alcohol and cannabis, totaling N=657 participants, of whom 496 reported simultaneous use. Participants who reported simultaneous use were directed to an open-response question assessing subjective effects from simultaneous use, relative to alcohol use alone, and 443 of the 496 simultaneous users provided usable data. Fifty-three participants either did not fill out the open-response question or gave uninterpretable data (e.g., a numerical value, “I don’t know”, “not sure”). The lead author removed cases in which participants who left a blank answer or entered an integer value (e.g., “1”, “100”), and then the coding team decided on responses that were entered but did not fit the purpose of the study (e.g., ‘addiction”, “I don’t know”, “not sure”). Thus, the current study only included individuals who reported simultaneous use and gave interpretable open-response data (N=443). Participants were 68.2% female, had a mean age of 19.85 (SD = 2.14), and identified as White (76.3%), Black/African American (4.7%), Asian (7.7%), Pacific Islander/Hawaiian (.5%), Native American/Indigenous (1.5%), and other (9.3%); 25.7% of the sample identified as Hispanic/Latinx.

Procedure

Participants were informed that they could earn extra credit in undergraduate psychology courses for research participation. If interested, participants were directed to an online portal where they could sign up, complete informed consent, and complete an online Qualtrics questionnaire. Once completed, participants were compensated one research credit toward their course and were thanked for their time. The Arizona State University Institutional Review Board approved all study procedures.

Measures

Simultaneous Alcohol and Cannabis Use.

Participants were asked, “How often do you use cannabis and alcohol at the same time—that is, so that their effects overlap?” on scale of 1 (I have Never) to 6 (Daily or Almost Daily). Participants were required to report a 2 (i.e., yearly to less than yearly) to be included in this study.

Simultaneous Use Subjective Effects.

If participants reported simultaneous alcohol and cannabis use, they were directed to an open-response question stating, “On days when people use alcohol and cannabis simultaneously (so that their effects overlap), some people say that the effects of alcohol are different than on alcohol-only days. How would you describe the difference in alcohol effects between simultaneous use days versus alcohol-only days?”.

Timeline Followback.

Participants completed an online, modified timeline followback interview (TLFB; Sobell & Sobell, 1992) assessing past 30-day alcohol use and simultaneous alcohol and cannabis use. Through an online portal, participants first reported which days during the past month they drank alcohol, and participants were then redirected to separate webpages for each reported drinking day. On each day, participants were asked to recall a noteworthy event, and were then asked to report the amount of alcohol consumed (0–20 drinks), negative alcohol consequences experienced (24 possible from the B-YAACQ; Read et al. 2006), whether cannabis was used that day (yes/no), and whether the effects of alcohol and cannabis use overlapped (yes/no) that day. Participants were provided with a standard drink chart and were encouraged to reference text messages, social media, and bank statements to aid in accurate reporting. Since this paper is focused on qualitative data from the open-response question, TLFB data are only presented in descriptive form to characterize the sample.

Data Analytic Plan

The current study used Conventional Content Analysis (Hseih & Shannon, 2005) to analyze text response data in terms of content and frequency of responses patterns. Conventional Content Analysis with open-response data is a popularly-used qualitative methodology in public health research (e.g., Barbosa-Leiker et al., 2021; Collins et al., 2014; Jones et al., 2015). Conventional Content Analysis consists of two primary steps. First, text data is gathered, and key phrases and words are highlighted as the basis for lower-order codes. Second, codes are grouped into higher-order concepts that are theoretically meaningful to help organize and understand the qualitative data. Consistent with this approach, data analysis in the current study consisted of two phases.

Phase 1: Codebook Development

First, the leading author extracted all text responses from a Qualtrics survey and input them into a Microsoft Excel file. The leading author read through all data to ensure that responses were in line with the prompt and purpose of the study, and he removed cases where participants left a blank answer or entered an integer value (e.g., “1”, “100”). Second, to reduce the possibility of confirmation bias by the lead author, the lead author shared the text responses with 12 study team members, and each team member was tasked with individually reviewing the data for codes that could be used to formally categorize the text responses. The 12 study members consisted of three team leaders (i.e., each with either a Ph.D. or M.A. in clinical psychology) and nine laboratory assistants (i.e., graduate and undergraduate research assistants). The lead author has taken courses in qualitative data analysis, the second author has published extensively with qualitative data, and the last author has used qualitative data to develop quantitative measures. All other team members were trained for the purpose of the current study.

After each of the 12 team members individually reviewed responses, three groups, each of which consisted of one team leader and three research assistants, were formed to generate a list of codes that represented the data. After each group came to agreement, the team leader shared their respective group’s codes with the larger group. Group-wide meetings of all 12 study members consisted of discussions about shared and unique codes across the groups, and all 12 team members contributed to an agreed upon structure of final codes. Once codes were agreed upon, the 12 study team members grouped codes into meaningful concepts. The leading author then created a master codebook with detailed information and examples for each concept and code (see Table 2). Concept and code names were decided by the team using a combination of participant language and research-derived phrases that represented certain constructs (e.g., impairment, crossfading). The laboratory team also decided to delete responses that were entered but didn’t fit the purpose of the study (e.g., ‘addiction”, “I don’t know”, “not sure”).

Table 2:

Qualitative Concepts and Their Frequencies from Individual Participant Data

List of Concepts and Codes	Description	N (% of sample)
1.1 Increased Impairment		191 (43%)
Intensity of Drunk/High	Stronger effects, more drunk/high, more pronounced	100
Behavioral	Feeling dizzy, less in control of body	48
Acute Physical	Feeling sleepier, more tired	42
Cognitive	Feeling confused, fuzzy headed, out of it	33
Slowed Down	Feel slowed down, a slowed effect, slower thinking	8
1.2 Decreased Impairment		55 (12%)
Intensity of Drunk/High	Weaker effects, less drunk/high, less pronounced	26
Behavioral	More in control, less dizzy,	20
Cognitive	Think more rationally, more aware, focused	11
Acute Physical	Less sleepy, less tired, less drowsy	6
2. Relaxation/Tension Reduction		115 (26%)
Calming/Relaxing Effects	Feeling more relaxed, calm, mellow	90
Less “up”	Feeling less energized, amped up	12
Satiation	Feeling smoother, warmer, lighter	9
Helps with Sleep	Easier to fall asleep, better sleep	8
Tension Reduction	Feeling less anxious, less depressed, less paranoid	5
3. Balancing/Replacement Effects		50 (11%)
Replacement	One substance replaces effects of the other	25
Balancing Out	One substance balances the other	17
Avoidance of Consequences	One substance inhibits consequences of the other	11
4. “Cross-Fading”		44 (10%)
Positive Affect Enhancement	Feeling happier, more fun, good, elated	28
Social Enhancement	Feeling increased sociability, easier to talk	9
More “up”	Feeling energized, amped up	7
Euphoria	Feeling euphoric effects	4
5. Little-To-No Differences	No marked difference in effects	30 (7%)
6. Altered Sensation & Perception		14 (3%)
Out of Body/Dissociation	Out of body/head, disconnected from reality, dream state	7
Heightened Sensations	More sensational, perceive world differently	7
7. Increased Negative Affectivity		15 (3%)
Increased Negative Affect	More anxious, angry	5
Increased Negative States	More dangerous, wild	10
8. Appetite Enhancement	Hungrier, likely to eat more food	5 (1%)
9.1 More Negative Consequences	Worse hangover, more blackout, more regrets	29 (7%)
9.2 Less Negative Consequences	Lesser hangover, less likely to blackout	39 (9%)

Note. Participants responses ranged from one word to several sentences, and thus several participant responses fit into several concepts and codes; all descriptions above come from exact textual language reported.

Phase 2: Coding

Once the codebook was finalized, the leading author as well as a senior research assistant applied the concepts and codes to each participant’s response, individually. Text data ranged from singular words to several paragraphs, and thus some responses fit into multiple concepts and codes. After the leading author and senior research assistant individually coded the data, they met to discuss and resolve any discrepancies. Percentage of agreement (percent of responses team coders agreed upon before resolving discrepancies) for codes was 92.1%, well above the recommended threshold of 80% (e.g., Guest et al., 2012). Data are available from the corresponding author upon reasonable request.

Qualitative Rigor.

The qualitative analysis was designed to be as rigorous as possible. In line with suggestions from Thomas & Magilvy (2011), efforts were made to enhance qualitative credibility, transferability, dependability, and confirmability. To enhance credibility, similar to internal validity, we 1) used direct participant language, and 2) included individuals with a variety of backgrounds and experiences in the coding teams, ranging from content and qualitative experts to college students with little research experience. To enhance transferability, similar to external validity, we outline demographic and substance use frequency, quantity, and problem data in an effort to make clear who the current concepts and codes may generalize to. To enhance dependability, similar to reliability, we 1) discussed our process step-by-step to make it repeatable by others, 2) had multiple coders rather than a singular coder, and 3) had college student (i.e., the target population) team members play an active role in coding. Finally, to enhance confirmability, similar to objectivity, we used a bottom-up, inductive process rather than seeking to confirm hypotheses. We also sought to continually challenge our biases throughout the coding process, with each team member having an active voice to challenge and/or agree with other team members’ conceptual arguments.

Results

Descriptive Statistics

Participants reported an average of 7.25 (SD = 5.17) past-month drinking days, of which 33.3% were simultaneous alcohol and cannabis use days. On average, participants reported consuming 4.50 (SD = 3.31) drinks on alcohol-only days and 5.40 (SD = 3.67) drinks on simultaneous use days. Participants reported an average of 2.02 (SD = 3.11) negative alcohol consequences on alcohol-only days and 2.98 (SD = 4.06) negative alcohol consequences on simultaneous use days (see Table 1 for descriptive statistics).

Table 1:

Descriptive Statistics

	Mean or %	SD
Demographic Variables
Age	19.85	2.14
Sex
Male	31.2%
Female	68.2%
Other	0.7%
Race/Ethnicity
White	76.3%
Asian/South Asian	7.7%
Black/African American	4.7%
Native American/Indigenous	1.6%
Hawaiian/Pacific Islander	0.5%
Other	9.3%
Ethnicity
Non-Hispanic/Latinx	74.3%
Hispanic/Latinx	25.7%
TLFB Person-Means
Past-month Drinking Frequency (Days)	7.25	5.17
Past-month Simultaneous Use Frequency (Days)	3.09	3.01
Past-month Drinking Quantity	4.80	3.46
Past-month Negative Alcohol Consequences	2.34	3.48

Note. TLFB stands for Timeline Followback.

Since the current study used textual response data, there was substantial variance in the amount of text provided. Thus, we examined the average number of words per response and whether number of words varied by age, sex, and simultaneous use frequency. Text responses ranged from 1 to 86 words, with an average of 12.32 (SD=11.63) words per response. Further, age (r=.03, p=.57), and sex (r=.05, p=.31) were not correlated with number of words per response, but more frequent simultaneous use was correlated with more words per response (r=.12, p=.01).

Qualitative Results on Subjective Effects of Simultaneous Alcohol and Cannabis Use

The 9 qualitative concepts that codes were grouped into included: (1) increased/decreased impairment, (2) low arousal/relaxation, (3) balancing/replacement effects, (4) “cross-faded” effects, (5) little-to-no differences, (6) altered sensation and perception, (7) increased negative affective states, (8) increased appetite, and (9) increased/decreased negative consequences.

Frequency of responses within the concepts and codes varied (Table 2). Below we describe the data within each concept and code along with representative quotes. We place more emphasis on more frequently endorsed concepts and codes but still describe those less frequently endorsed.

1.1. Increased Impairment.

The most commonly applied concept was increased impairment; a total of 191 participants (43%) reported subjective effects that fell into the code of increased intoxication and cognitive/bodily impairment when simultaneously using. Within this code, the most popularly reported subjective effect was feeling increased intensity of intoxication and stronger alcohol/cannabis effects (n=100). For example, participants stated:

“I would say that cannabis while drinking just increases the effects of alcohol” (participant 671), “I definitely feel the effects more when using both simultaneously” (participant 700) and “Less alcohol hits way harder if I have any weed in my system…” (participant 717).

Participants also reported specific impairment related to behavioral (n=48; e.g., dizzier, head spins, out of control), physical (n=42; e.g., more tired, fatigued), and cognitive (n=33; e.g., more out of it, zoned out, less aware) capabilities. For instance, participants stated:

“I feel more out of it than on only alcohol days” (participant 324), “[I feel] more drowsy in the body, more intoxicated feeling, more memory loss” (participant 200), and “On simultaneous days I feel much more dizzier, I slur my words more, I have blurred vision and a sort of dragged vision more than I do on alcohol-only days…” (participant 148).

Finally, 8 participants reported being “slowed down”, or moving/talking slower. For instance, participants stated:

“The time goes a lot slower on simultaneous days” (participant 24) and “Weed adds a slow effect to the drunkness” (participant 414), and “Everything happens so slow” (participant 760).

1.2. Decreased Impairment.

A total of 55 participants (12%) reported subjective effects that largely fell into the concept of lesser intoxication and decreased cognitive/bodily impairment. First, 26 participants reported feeling less intense intoxication, weaker subjective effects, and/or less drunk/high. For example, participants stated:

“[I feel] less of an effect; cannabis lessens impact” (participant 208),“The effect of alcohol is less potent with cannabis than without cannabis” (participant 341), and “I feel as though the effects cancel each other out for the most part or aren’t as intense than the days where it is only alcohol” (participant 363).

Opposite to concept 1.1, some participants reported less impairment related to behavioral (n=20; e.g., less dizzy, more in control), cognitive (n=11; e.g., less out of it, more aware), behavior (n=20; e.g., less dizzy, more in control), and physical (n=6; e.g., less tired, less drowsy) capabilities. For instance, participants stated:

“It feels more focused, controlled, and relaxing when combining weed and alcohol” (participant 97), “Cannabis and alcohol make me feel more in control as opposed to just alcohol” (participant 167), and “[I am] able to process information more clearly, felt less intoxicated (i.e., dizzy, disoriented), more relaxed” (participant 589).

2. Low Arousal/Relaxation.

A total of 115 participants (26%) reported responses in line with relaxation and tension reducing subjective effects from simultaneous use. Ninety participants reported feeling more relaxed, calm, and mellow on simultaneous use days. For instance, participants stated:

“When used with cannabis, the effects of alcohol are much more relaxing than alcohol only days” (participant 133), “Simultaneous use makes the alcohol more relaxing and less nauseous” (participant 160), and “[I feel a” more mellow/chilled out feeling” (participant 215).

In addition, 12 participants reported feeling less energetic and less “up”/amped, nine participants reported satiation effects such as feeling “smoother”, “warmer”, and “lighter”, and eight participants reported increased ability to fall asleep and have higher quality sleep from simultaneous use. For instance, participants stated:

“On days where I use both I either get much more or much less energy than just drinking” (participant 569), “[I feel] warmer, more calm, less likely to be very sociable” (participant 213), and “The difference is that cannabis usually calms me down more and makes it easier for me to sleep after drinking” (participant 6).

Finally, five participants reported tension reduction from negative affect, such as anxiety, depression, and paranoia. For instance, participants stated:

“[I feel] less anxiety when using simultaneously” (participant 481), “I am more relaxed with simultaneous use days, and I don’t get as paranoid” (participant 180), and “…the anxiety is removed and my sociability goes up” (participant 212).

3. Balancing/Replacement Effects.

A total of 50 participants (11%) reported subjective effects related to the concept of balancing/replacement effects, described as using one substance to substitute the effects of the other. First, 25 participants reported that simultaneous use replaces/rids the body of the first substance and/or has a “sobering” effect. For instance, participants stated:

“The high feeling takes over” (participant 35), “for me, the high overcomes the buzzed feeling from the alcohol so i end up mostly just feeling high” (participant 249), and “When substances are combined it has this sobering effect, but it is your two states combining making you simply feel good” (participant 279).

Second, 17 participants reported that using cannabis balances out of the effects of alcohol. For example, participants stated:

“…mixing alcohol and weed together creates a nice leveling sensation. It kind of simmers down the effects of alcohol” (participant 150), “[Simultaneous use is a] balancing act between the two substances” (participant 157), and “Using both allows for the buzz of alcohol to meet the relaxed state of cannabis” (participant 368).

Third, 11 participants reported that simultaneously using cannabis with alcohol potentiates negative reactions from alcohol use. For instance, participants stated:

“Marijuana nullifies the negative effects of alcohol” (participant 720), “The alcohol effects are not as bad” (participant 204), and “The cannabis use helps to limit the effects of alcohol and usually eliminates the nausea and hangover” (participant 750).

4. Cross-Faded/Enhancement Effects.

A total of 44 participants (10%) reported responses in line with “cross-fading”, or enhancement of positive and social experiences, from simultaneous use. Specifically, 28 participants reported enhanced positive affective states, such as feeling happier, sillier, and feeling “better”. For instance, participants stated:

“…When I drink AND smoke, I feel sociable, balanced, and happy. The anxiety is removed and my sociability goes up” (participant 212), “I feel more fun” (participant 479), and “Mixed times are happier times” (participant 99).

Also within this concept, nine participants reported feeling more sociable/social and talkative when simultaneously using, seven participants reported feeling more “up” and/or “amped up”, and four participants reported feeling increased “euphoria” or “euphoric” effects. For instance, participants stated:

“I am able to become more social…” (participant 619), “Using both together make you feel more up as opposed to down” (participant 333), and “When using cannabis an alcohol together there is a heightened euphoria” (participant 231).

5. Little-To-No Difference.

Thirty participants (7%) reported that simultaneously using alcohol and cannabis did not lead to much of a difference relative to alcohol only use. Most responses were either “not different” or “no difference”. However, more descriptively, participants stated:

“Not too different. The cannabis didn’t really work” (participant 790), “I never notice a difference” (participant 693), and “Seems pretty much the same” (participant 151).

6. Altered Sensations and Perceptions.

A total of 14 participants (3%) reported altered sensation and/or perception when simultaneously using. Seven participants reported having dissociative experiences, such as feeling out of body, out of head, and in a dream-like state. For instance, participants stated:

“Simultaneous use greatly effects my balance and also makes me feel more disconnected from reality,” (participant 496),“It gives you more of an out of body experience” (participant 70), and “Feeling a lot more out of it and like a dream state, cannot process what is happening around you, at least in my experience” (participant 169).

In addition, seven participants also reported feeling heightened/differing sensations. For instance, participants said:

“It’s a heightened sensation of the five senses rather than the wooziness and loss of control alcohol is” (participant 627), “I have more of a realization of your body and feeling things” (participant 489), and “You feel every movement and noise but it happens slow and without thought” (participant 119).

7. Increased Acute Negative Affective States.

Fifteen participants (3%) reported feeling increased negative affective states when simultaneously using alcohol and cannabis. First, in direct contrast to increased tension reduction, five participants reported feeling increased negative affect, particularly anxiety, anger, and stress. For example, participants stated:

“[I feel] more stressed on simultaneous days than alcohol days” (participant 698), “I feel more anxious and nervous when I simultaneously use cannabis than when I just drink” (participant 747), and “The feeling is different, sometimes unpleasant…” (participant 735).

In addition, 10 participants reported increased negative states, such as feeling “not good”, “worse” and “crazy”. These responses were separated from acute negative affect as we conceptualized them more as negative states than negative affect. For instance, participants said:

“I’m more high strung on days I used cannabis and alcohol” (participant 370),“In simultaneous use, I feel worse than only drinking alcohol” (participant 334), and “alcohol just makes you woozy together it makes you crazy” (participant 394).

8. Increased Appetite.

Five participants (1%) reported having increased appetite and hunger when simultaneously using alcohol and cannabis. For instance, participants stated:

“Alcohol only days leave me sick and not wanting to eat, while simultaneous use allows me to still have an appetite” (participant 114), “It makes me dizzier and want to eat…” (participant 722), and “[I feel] more tired and hungry” (participant 541).

9. Negative Consequences.

Although participants were asked about their subjective effects from simultaneous use vs. alcohol-only use, a substantial number (N=65; 15%) reported on their experience of negative consequences. However, participants were nearly split on whether simultaneous use conferred risk for increased versus decreased risk for negative consequences. A total of 29 participants reported that simultaneous use increased hangovers, blackouts, and nausea. For instance, participants stated:

“Hangover is worse” (participant 688), “When I overlap, I completely black out” (participant 159), and “Simultaneous days make me more dizzy and out of it and more prone to throwing up” (participant 653).

In contrast, 39 participants reported lesser hangovers, blackouts, and nausea/upset stomach. For instance, participants stated:

“…I tend to not get hangovers when I smoke” (participant 3), “Simultaneously: More Relaxed and Focused; Alcohol-Only: More likely to black-out” (participant 385), and “I do not feel as nauseous” (participant 762).

Discussion

Research consistently suggests that simultaneous alcohol and cannabis use (vs. alcohol-only use) is associated with negative alcohol outcomes, including heavier drinking and more negative alcohol consequences (e.g., Gunn, Aston, & Metrik, 2022; Lee et al., 2022). However, little is known about mechanisms through which simultaneous use confers risk. One mechanism may be subjective response to simultaneous use, but studies to date have used pre-determined, non-specific subjective effects to assess subjective response to simultaneous use (e.g., “drunk”, “high”, “intoxicated”). Therefore, the current study used formative, qualitative data analysis to identify how subjective effects of simultaneous use vs. alcohol-only use differ based on textual data from participants. The current study assessed a) whether specific effects are enhanced by simultaneous vs. alcohol-only use, and b) whether simultaneous use is associated with unique effects that are not currently on alcohol and cannabis subjective effects scales. Through Conventional Content Analysis, nine concepts were evident in the data: (1) increased/decreased impairment, (2) low arousal/relaxation, (3) balancing/replacement effects, (4) “cross-faded” effects, (5) little-to-no differences, (6) altered sensation and perception, (7) increased negative affective states, (8) increased appetite, and (9) increased/decreased negative consequences.

Impairment During Simultaneous Use

The most frequently reported qualitative concept was increased impairment, which included increased intoxication, increased cognitive, behavioral, and physical impairment, and feeling more slowed down. These subjective effects largely map onto the sedation subscale of the Biphasic Alcohol Effects Scale (BAES; Martin et al., 1993) and the low arousal negative subscale of the Subjective Effects of Alcohol Scale (SEAS: Morean et al., 2013). Furthermore, these qualitative findings support past studies suggesting that simultaneous alcohol and cannabis use is associated with feeling more “drunk” and “intoxicated” compared to alcohol-only use (e.g., Lee et al., 2017; Lipperman-Kreda et al., 2017; Sokolovsky et al., 2021). Although feeling increased “drunk” and “intoxication” were frequent responses within this concept, there were a range of responses and subjective effect terminology that are not currently present in the simultaneous use and/or alcohol literature. For example, participants reported sedative effects such as feeling “fuzzy-headed”, “out of it”, and “less in control.” None of these effects are found on the BAES or the SEAS. Participants also reported subjective effects related to sleep impairment (e.g., feeling fatigued, tired) and feeling “slowed down”, which are similar yet distinct to sedation/low arousal negative effects.

There was substantial heterogeneity in how participants described increased intoxication from simultaneous use. Some participants reported heightened “intoxication”, some participants reported heightened feelings of “drunk”, and other participants reported heightened feelings of “high”. However, it was unclear if these terms mean different things. For instance, one participant stated: “the high feeling takes over”, suggesting that feeling “high” may be different than feeling “drunk”. This discrepancy may be important when describing impairment, as “high” and “drunk” are often thought to be related/identical indicators of impairment from simultaneous alcohol and cannabis use (e.g., Linden-Carmichael et al., 2020).

Although increased impairment was the most popularly endorsed subjective effect from simultaneous use, 12% of the sample reported that they felt less impairment when simultaneously using. Thus, there was variability as to whether cannabis conferred increased versus decreases risk for impairment. There was also variability in language used to describe increased vs. decreased impairment. For instance, some participants reported being “out of it” and “dizzy” (increased impairment), whereas other participants reported being more “aware” and “focused” (decreased impairment) when simultaneously using. This suggests that, particularly when quantitatively assessing impairment from simultaneous use, it may be important to include subjective effects that are indicative of heightened as well as decreased impairment to fully assess subjective effects of simultaneous use.

Positive Effects During Simultaneous Use

In line with past literature (e.g., Patrick et al., 2020; Patrick & Lee, 2018), “cross-faded effects” were evident in the data. These largely involved positive affect enhancement and increased sociability. However, responses that fit within this concept were not especially common, reported by only 10% of participants. Furthermore, it is important to note that the literature on cross-fading motives does not differentiate which positive effects are enhanced – for example, one item on Patrick et al. (2020)’s cross-fading motives questionnaire is: “I used alcohol and marijuana at the same time to increase the positive effects I get from alcohol” (Patrick et al., 2020). Thus, future work should consider differentiating positive effects such as feeling “sociable”, “talkative”, “happy”, “euphoric”, and “energized”, which were popular cross-fading text responses in the current study. Of note, the subjective effects described in this concept, except for “euphoria”, are on the stimulation and high arousal positive factors of the BAES and the SEAS (Martin et al., 1993; Morean et al., 2013), and thus future quantitative work should assess the outcomes of increased stimulation during simultaneous vs. alcohol-only use.

There was a distinct (and commonly endorsed) set of responses that fit into the domain of relaxation/tension reduction, which largely represented low arousal positive effects found on the SEAS (Morean et al., 2013). In line with the alcohol literature, this suggests that differentiating low arousal subjective effects based upon valence (i.e., low arousal negative vs. low arousal positive) may be important when assessing subjective effects of simultaneous use (Morean et al., 2013). In addition to feeling low arousal positive effects such as “relaxed”, “mellow”, and “calm”, participants also reported relief from negative affect/tension reduction, satiation effects (e.g., feeling smoother, warmer), enhanced sleep, and feeling less amped up. Importantly, sleep-related responses within this concept were indicative of better sleep and/or easier ability to fall asleep, as compared to sleep-related impairment/fatigue within the concept of increased impairment. Thus, quantitative work should consider differentiating for whom and when simultaneous use is associated with increased sleep-related impairment (i.e., fatigue) versus increased ability to fall and stay asleep.

Balancing/Replacement Subjective Effects

Eleven percent of participants (N=50) reported balancing/replacement effects when simultaneously using, such that cannabis balanced out the effects of alcohol, replaced the effects of alcohol, and/or rid the body of alcohol effects. These qualitative findings support other qualitative work finding harm-reduction related motives for simultaneous use (Boyle et al., 2021), as well as quantitative studies finding that co-using for substitution reasons is associated with lesser risk (Gunn et al., 2019). Taken together, balancing/replacement effects may be protective against negative alcohol outcomes, but this warrants further research.

Other Subjective Effects

Although less common, there were also responses that fit into categories of altered sensation and perception, increased negative affect, and increased hunger. For altered sensations, little specificity of effects was given in text responses; rather, it appeared that sensations overall were heightened, in line with effects such as “heightened sensations” that appear on cannabis expectancy measures (e.g., Conner et al., 2011; Waddell et al., 2020b). For altered perception, there appeared to be acute psychosis-related experiences, such as feeling “out of body” and “disconnected from reality”, in line with cannabis administration studies showing increased psychosis symptoms during cannabis use (D’Souza et al., 2009). Thus, responses that fit in this category may have been largely driven by cannabis use. Second, there was a category of subjective effects that indicated an increase (rather than decrease) in negative affectivity. Since similar effects were present in the relaxation/tension reduction code, future quantitative work should consider including negative affect items, which can then be endorsed as increases vs. decreases in such effects. Finally, several participants reported being hungrier and having increased appetite. Although not necessarily a subjective effect, it appears that simultaneous use may instill risk for the “munchies” similar to cannabis-only use (e.g., Roberts et al., 2019).

Outcomes of Simultaneous Use

Participants were asked to report on subjective effects from simultaneous use versus alcohol-only use, but a substantial percentage of participants reported on negative consequences from simultaneous use. Participants were nearly split as to whether simultaneous use conferred risk for more negative consequences (6.5% of participants) versus fewer negative consequences (8.8% of participants). Furthermore, participants consistently reported the same negative consequences in both directions: more/less hangovers, nausea, blackouts, and next-day regrets. These qualitative responses provide several important avenues for future research, primarily investigating for whom simultaneous use may confer increased versus decreased risk for negative consequences.

One factor may be an individual’s frequency of simultaneous use. An individual who infrequently engages in simultaneous use may do so without the reinforced notion that negative consequences may be heightened, whereas an individual who frequently simultaneously uses may be accustomed to such consequences and may have built up tolerance. Another possibility is that motivation and level of consumption differentiate for whom simultaneous use is related to more vs. fewer negative consequences and impairment. Theory suggests that simultaneous use to complement is associated with heavier drinking whereas simultaneous use to substitute is associated with less drinking (e.g., Gunn et al., 2019). Thus, people who simultaneously use to substitute may report lesser drinking when simultaneously using, which would naturally be related to fewer negative consequences. Future quantitative work is needed to address these hypotheses.

The findings of the current study may inform intervention and prevention efforts related to simultaneous alcohol and cannabis use. First, since increased cognitive/behavioral impairment was the most often reported subjective effect concept, and impairment is often viewed as aversive/negative (i.e., Fromme et al., 1993; Morean et al., 2012), it is possible that individuals expect positive effects from simultaneous use but may not necessarily experience these effects. In support of this possibility, positive simultaneous use expectancies are reported much more frequently than expectancies of cognitive/behavioral impairment (Waddell et al., 2022b). Thus, it is possible that aligning one’s expectancies with such impairment via an expectancy challenge intervention (e.g., Darkes & Goldman, 1994) could decrease engagement in simultaneous use, leading to potentiated risk for negative outcomes. However, quantitative research is needed to address this hypothesis. Second, since there were concepts focused on both positive and negative reinforcement (i.e., cross-fading, relaxation/tension reduction), medications such as Naltrexone, which blunt the reinforcing subjective effects of alcohol (e.g., O’Malley et al., 2015), could also be effective at reducing simultaneous use. However, quantitative research is needed to address this hypothesis.

Limitations

The current findings should be interpreted in light of study limitations. First, participants in the current study were college students and it is unclear if subjective effects from simultaneous use are similar in other populations. Second, the current study used open text responses to a singular prompt, rather than in-depth interviews. Although this allowed us to obtain a large number of responses to generate substantive concepts and codes, this approach did not allow us to ask follow-up questions about a participant’s text responses if they were ambiguous. Relatedly, textual responses to the open-ended question ranged from a few words to a few paragraphs. Thus, longer participant responses provided more detailed information compared to responses that were only a few words such as “I feel better”.

Third, participants were primed to think about differences between simultaneous use and alcohol-only use, and the question wording could be interpreted as suggestive, encouraging participants to respond in a manner they would not have otherwise. However, a substantial percentage of participants still reported no differences in subjective effects for simultaneous vs. alcohol-only use (7%). Nonetheless, the current study did not independently assess alcohol-only and simultaneous use subjective effects, but rather asked participants to report on the difference between the two. Future research is needed to replicate these findings using more basic textual response or interview data on both types of subjective experiences.

Fourth, the current study focused on substantive concepts and codes across all participants and did not differentiate codes/concepts within specific groups (e.g., men and women, those who engage in simultaneous use more frequently versus less frequently). Fourth, there may be several unmeasured factors unique to simultaneous versus alcohol-only use (e.g., social context, number of drinks consumed, day of week; Boyle et al., 2022; Gunn et al., 2021; Jackson et al., 2021) that could explain differences in subjective effects, and those could not be evaluated here. Fifth, the current study assessed differences in subjective effects of simultaneous use as compared to alcohol-only subjective effects but did not ask participants about the difference in subjective effects from simultaneous use as compared to cannabis-only use. Sixth, the current study measured retrospectively reported subjective effects, which is a similar construct to expectancies. Thus, future research is needed to differentiate simultaneous use expectancies from subjective effects, as research suggests that expectancies often modulate the effects of subjective response on acute outcomes (e.g., Gunn et al., 2017; Morean et al., 2015; Waddell et al., 2020a).

Conclusions

The current study is the first to differentiate subjective effects from simultaneous alcohol and cannabis vs. alcohol-only use using formative, qualitative analyses. The current study identified 9 distinct subjective response concepts, including (1) increased/decreased impairment, (2) low arousal/relaxation, (3) balancing/replacement effects, (4) “cross-faded” effects, (5) little-to-no differences, (6) altered sensation and perception, (7) increased negative affective states, (8) increased appetite, and (9) increased/decreased negative consequences. Several concepts matched constructs that are already present in the literature (e.g., increased impairment, cross-fading subjective effects, balancing/replacement effects), however the language used in textual responses suggested specific effects within these concepts that are enhanced vs. reduced from simultaneous alcohol and cannabis use (e.g., feeling out of it, focused, happy, euphoric). The current study also found distinct concepts related to the subjective experience of simultaneous use (e.g., altered sensations and perceptions, increased negative affectivity) that are not currently described in the literature. Overall, qualitative concepts and codes in the current study can inform theory and continued research related to simultaneous use and related risk. Future quantitative research is needed to 1) validate a measure of subjective effects of simultaneous use, and 2) assess whether specific subjective responses to simultaneous use relate to drinking patterns (i.e., heavier consumption, more negative consequences/dependence symptoms) and different contexts (i.e., social and physical context). Future research is also needed to test whether concepts and codes related to subjective responses to simultaneous use differ as a function of how frequently one simultaneously uses alcohol and cannabis.

Public Health Significance:

Subjective effects are a mechanism through which addictive behaviors are reinforced, however little is known about the subjective effects of simultaneous alcohol and cannabis use compared to using alcohol alone. Using qualitative data analysis, the current study of college students found that several alcohol/cannabis subjective effects are enhanced by simultaneous use, and that simultaneous use is also associated with unique effects. Findings may inform theoretical models of simultaneous use and prevention efforts focused on the subjective experience of simultaneous alcohol and cannabis use.