Interpretations and Experiences of Subjective Effects for Alcohol Alone and When Combined with Cannabis: A Mixed-Methods Approach

Abstract

Subjective effects generally describe the feelings one has when consuming substances. There are several tools available for measuring alcohol-related subjective effects but there are reasons to believe that effects are interpreted differently across participants. The assessment of alcohol-related subjective effects is further complicated by the fact that many people use other substances with alcohol, including cannabis. The current study used a mixed-methods approach to evaluate interpretations of 21 subjective effects used in common assessments among a college student sample (N=99; primarily White [79%], Hispanic [60%] women [74%], 72% of which reported lifetime co-use of alcohol and cannabis). We sought to a) estimate the prevalence of each effect and the amount of alcohol/number of drinks (and, for those with simultaneous use, amount of cannabis/number of hits) required to experience each effect and b) evaluate how participants interpreted each effect that they had ever experienced when drinking (for our sample who had used only alcohol) or when simultaneously using alcohol and cannabis (for our sample who had reported simultaneous use). Across both samples, we found that several effects were far more common than others and participants had varied interpretations of each subjective effect. Further, qualitative results demonstrated that participants interpreted some subjective effects in a way that differed from the original intention of the measure. Results suggest a degree of measurement error when using common subjective effects assessment tools. Findings lay the groundwork for standardized measures of subjective effects for simultaneous use and have implications for future real-world assessment and intervention work.

Alcohol-related subjective effects, or feelings one has when consuming alcohol, are strongly related to alcohol use outcomes including level of alcohol used and alcohol-related harms (Lau-Barraco & Linden-Carmichael, 2019; Quinn et al., 2013). Subjective effects can be a key element in one’s decision-making process when drinking: for example, individuals often use internal feelings of intoxication to help determine whether they are sober enough to drive home after drinking, which may differ from their actual level of impairment (see Aston & Liguori, 2013). Numerous scales have been developed to identify subjective effects including a focus on stimulant (e.g., energized) and sedative effects (e.g., drowsy; Biphasic Alcohol Effects Scale; Martin et al., 1993), subjective effects that vary by valence and arousal (e.g., wobbly, talkative; Subjective Effects of Alcohol Scale; Morean et al., 2013), and the number of drinks needed to achieve a response during various time periods (i.e., Self-Rating of the Effects of Alcohol; Schuckit et al., 1997) and when using lower (e.g., feeling ‘buzzed’) or higher doses of alcohol (e.g., feeling dizzy; Alcohol Sensitivity Questionnaire; O’Neill et al., 2002).

Individual Differences in Alcohol-Related Subjective Effects

Although these alcohol-related subjective effects scales are widely used and predictive of concurrent and future alcohol use behaviors (e.g., Bartholow et al., 2007; Fleming et al., 2016; King et al., 2014), there are several critical measurement considerations relevant to assessing subjective effects. First, specific effects measured vary widely by scale and a body of work focusing specifically on intoxication-related language suggests that individuals perceive certain terminology differently (e.g., Cameron et al., 2000; Levitt et al., 2009). Levitt and colleagues (2009) assessed (1) whether individuals were familiar with/personally used individual intoxication terms (e.g., inebriated, loaded) and (2) how many drinks it would take to experience each effect. Language was found to vary widely and commonly used words such as ‘drunk’ which are used in many daily diary studies (e.g., ‘how drunk do you feel’ on a 0–100 slider; (Heinz et al., 2013; Quinn & Fromme, 2012) and scales such as the Anticipated Effects of Alcohol Scale (Morean et al., 2012), were interpreted differently across participants in terms of the amount of alcohol needed to experience this effect.

Similar findings demonstrating that words such as ‘drunk’ have varied interpretations were observed in more recent work in which individuals were asked to self-generate and rank order intoxication language (Linden-Carmichael, Masters, et al., 2020; Linden-Carmichael et al., 2021). Here, ‘drunk’ was self-generated by most participants; however, of those, 3% identified drunk as a word used to describe a ‘light’ drinking occasion, 31% identified this as a ‘moderate’ drinking occasion, and 66% identified this as a ‘heavy’ drinking occasion. Other work has found that definitions of words such as ‘drunk’ vary by individual differences including level of alcohol consumed during a typical occasion (Reich et al., 2012), gender (Kerr et al., 2018), and culture or region (Thickett et al., 2013). These findings have key measurement implications of subjective effects, yet such in-depth qualitative and quantitative examinations of perceptions of terminology have primarily focused on intoxication-related language. Understanding how individuals interpret other commonly used cognitive (e.g., “difficulty concentrating”) and physical (e.g., “numb”) effect items, as well as whether and how much alcohol one would require to experience each effect may be equally useful for understanding subjective effects that may be used to guide decision-making when drinking and be related to other relevant outcomes (e.g., likelihood of experiencing harms).

Subjective Effects of Alcohol Use When Combined with Cannabis

A major consideration for measurement of alcohol-related subjective effects is the role of other substance use. While rates of alcohol use on college campuses have remained high and generally plateaued or even declined, rates of cannabis use have escalated in recent years with more than 1 in 10 young adults reporting daily or near daily cannabis use (Patrick et al., 2022). Many college students and young adults use both alcohol and cannabis and, of individuals who use both, many use both substances at the same time so that their effects overlap (or report “simultaneous use”; Subbaraman & Kerr, 2015). In line with historical increases in rates of cannabis use, simultaneous use of alcohol and cannabis has increased in prevalence: an estimated 25% of young adults who consume alcohol also report simultaneous use (Terry-McElrath & Patrick, 2018). Importantly, relative to individuals who use only alcohol, individuals who engage in simultaneous use are at increased risk for heavy substance use and negative alcohol-related consequences including adverse physical effects, blacking out (i.e., alcohol-induced memory loss during a drinking occasion), and use disorders (Jackson et al., 2020; Lee et al., 2022; Linden-Carmichael et al., 2019). Furthermore, among individuals who report simultaneous use, days involving simultaneous use confer greater risk for harms relative to days with only alcohol or cannabis (Lee et al., 2020; Linden-Carmichael, Van Doren, et al., 2020; Sokolovsky et al., 2020) although mixed findings have been reported such that number of negative consequences experienced did not differ between heavy drinking occasions with versus without cannabis use (e.g., Mallett et al., 2019).

A limited but growing body of work has explored how subjective effects may differ when combining alcohol and cannabis relative to when using only alcohol. Diary and momentary work have produced mixed findings: whereas some studies found that level of subjective intoxication did not differ between days with simultaneous use (Linden-Carmichael, Masters, et al., 2020), others found that feelings of drunkenness (Lipperman-Kreda et al., 2017) and intoxication (Sokolovsky et al., 2020) were higher on simultaneous use days. Retrospective assessments also suggest that sedative effects of use (e.g., dizzy, clumsy, confused, drunk) are also self-reported to be higher when combining relative to using only alcohol (Lee et al., 2017). Recent qualitative work has specifically identified language young adults use to describe how they feel when combining (Abrams et al., 2022; Waddell et al., 2023). Most commonly, college students reported that impairment and relaxation was higher when simultaneously using relative to using only alcohol (Waddell et al., 2023). When asked to retrospectively self-report subjective states at lower/higher levels of alcohol/cannabis use within a simultaneous use episode, young adults were found to have a wide range of vocabulary for describing subjective states and that language varied greatly across different combinations of use and as a function of the level of alcohol and cannabis used. Vocabulary also varied by age and typical substance use behavior (Abrams et al., 2022). With the exception of feeling “cross-faded” (i.e., feeling the effects of alcohol and cannabis at the same time) when combining, both studies found that the majority of subjective effects were not necessarily unique to simultaneous use but mapped on to general domains of alcohol (e.g., buzzed) or cannabis (e.g., stoned) subjective states. Overall, however, it is clear that combining alcohol and cannabis is perceived to alter one’s subjective state in a variety of ways and more research is needed in this area.

Current Study

Building on formative work by Levitt et al. (2009) and Linden-Carmichael et al. (2020) who conducted in-depth explorations of intoxication-related terminology, the current study used a mixed-methods approach to evaluate participant interpretations of subjective effect items used in common assessments. We combined terms across the most widely used subjective effects scales to address two aims drawing from two samples: (1) college students who had used alcohol but not simultaneously with cannabis and (2) college students who had ever engaged in simultaneous alcohol and cannabis use. First, we sought to examine the prevalence of experiencing each effect and the amount of alcohol/number of drinks (and, for our simultaneous use sample, amount of cannabis/number of hits) required to experience each effect. Second, via open-ended questions, we inquired how participants interpreted each effect that they had ever experienced when drinking (for our sample who had used only alcohol) or when simultaneously using alcohol and cannabis (for our sample who had reported lifetime simultaneous use). As an exploratory aim, we also asked our sample who reported lifetime simultaneous use how they interpreted the common framing of simultaneous use (i.e., used alcohol and cannabis ‘so that their effects overlapped’).

Method

Participants and Procedures

Participants were recruited through introductory psychology courses at a large Hispanic-serving southwest university in a state in which recreational¹ and medical cannabis use was legal. To be eligible, participants had to be at least 18 years of age and report drinking alcohol on at least one occasion in the past 30 days AND report heavy episodic drinking (5+ [male]/4+ [female] drinks in a single sitting) at least once in the past 12 months. A total of 172 individuals completed the survey. However, 73 participants were excluded from the current analyses because they did not drink in the past 30 days (n = 37), did not report heavy episodic drinking in the past 12 months (n = 34), or completed less than 95% of the survey (n = 2). The resulting sample thus included 99 participants who were 21.34 years of age on average (SD = 3.58) and primarily White (78.79%), Hispanic (59.60%) women (73.74%). Most participants reported lifetime simultaneous use (72.73%) and recent heavy drinking (past 30-day maximum drinks M = 10.97, SD = 5.96). Full sociodemographic and substance use information is provided in Table 1.

Table 1.

Sample Sociodemographics (N = 99)

	%	n	M	SD	n missing
Age			21.34	3.58	5
Sex					1
Female	74.75	74
Male	24.24	24
Intersex	0.00	0
Gender					1
Woman	73.74	73
Man	22.22	22
Genderqueer	1.01	1
Gender non-conforming	1.01	1
Non-binary	1.01	1
Transgender	0.00	0
Racial Identity					0
Alaskan Native	4.04	4
Black or African American	4.04	4
Chinese	1.01	1
Filipino	2.02	2
Guamanian	0.00	0
Indian	1.01	1
Japanese	0.00	0
Korean	0.00	0
Middle Eastern	0.00	0
Native American	3.03	3
Native Hawaiian	0.00	0
Samoan	0.00	0
Vietnamese	0.00	0
White	78.79	78
Not listed	6.06	6
Hispanic	59.60	59			1
Family history of alcohol-related problems
Yes, both biological mother and father	12.12	12
Yes, biological mother	10.10	10
Yes, biological father	22.22	22
No, neither	42.42	42
Don’t know	11.11	11
Lifetime drug or alcohol treatment	6.06	6			1
Lifetime maximum drinks			18.24	8.35	2
Past 30-day maximum drinks			10.97	5.96	0
Past 3-month average drinks/week			2.28	1.24	0
Past 3-month average weekday (Sun-Th) drinks/week			1.50	0.94	0
Past 3-month average weekend (Fri-Sat) drinks/week			4.23	2.64	0
Lifetime simultaneous use	72 .73	72			0

Note. Participants could have endorsed more than one racial identity. Other racial identities not listed that were endorsed included Hispanic, Latino, and Mexican.

After providing electronic informed consent through Qualtrics, participants completed a series of questions to determine eligibility. If eligible, they proceeded to several electronic questionnaires that took approximately 30 minutes to complete. In the first block of questions, participants were asked whether they had ever simultaneously used alcohol and cannabis. If participants denied lifetime simultaneous use, they were only asked about alcohol-related subjective effects. If participants endorsed lifetime simultaneous use, they were asked about simultaneous use effects. Participants were compensated for their participation with course credit. All methods and procedures were reviewed by the university’s institutional review board. This study was not preregistered and we did not conduct formal a priori power analyses given the mixed-methods, descriptive nature of the manuscript.

Measures

Lifetime simultaneous use.

Participants were asked, “Have you ever used alcohol and marijuana² at the same time – that is, so that their effects overlapped?” where an affirmative response indicated lifetime simultaneous use of alcohol and cannabis.

Subjective effects.

Twenty one subjective effects were selected from existing self-report subjective effects questionnaires including the ASQ (O’Neill et al., 2002), a four-anchored slider (Linden-Carmichael, Masters, et al., 2020; Linden-Carmichael & Calhoun, 2021), SRE (Schuckit et al., 1997), SEAS (Morean et al., 2013), BAES (Martin et al., 1993); AEAS (Morean et al., 2012), Sensation Scale (Adesso & Lauerman, 1975; Maisto et al., 1980), a modified version of the Subjective High Assessment Scale (SHAS-7) adapted for cannabis use and simultaneous use (Eng et al., 2005; Lee et al., 2017), and qualitative reports of simultaneous use effects (Abrams et al., 2022). First, all effects from each scale were compiled (see Supplemental Table 1). Next, through consensus, the authors selected those effects that were cognitive or physical (rather than emotional or behavioral) in nature to tease apart effects from the substance(s) used rather than effects that may be due to other reasons, such as features of the social environment (e.g., flirtatious, rude) or that are primarily a consequence of substance use rather than a subjective effect of use (e.g., blackout, vomit). Then, effects that were deemed to be similar were combined (e.g., difficulty concentrating and difficulty with thinking were combined to “difficulty thinking”), resulting in a final list of 21 subjective effects for inclusion in the current study (presented in Table 2).

Table 2.

(A) Alcohol (n=27) and (B) Simultaneous Use (n=72) Subjective Effects

(A)			Amount of Alcohol (Small [1] to Large [10]) to Experience Effect			Number of Drinks (0–20+)to Experience Effect			Abs. Rank Diff.
Subjective Effects	%	n	M	SD	Rank	M	SD	Rank
Breathing changes	22.22	6	7.00	3.22	1	8.83	4.96	1	0
Upset stomach	48.15	13	6.69	2.78	2	6.38	4.01	6	4
Difficulty thinking	29.63	8	6.62	3.02	3	8.12	5.30	2	1
Impaired vision	33.33	9	6.22	2.73	4	6.89	5.23	3	1
Head throbbing	33.33	9	6.11	2.37	5	6.67	4.64	5	0
Sluggish	29.63	8	5.88	2.70	6	6.25	4.71	9	3
Slurred speech	48.15	13	5.77	3.03	7	6.38	3.50	7	0
Numb	29.63	8	5.62	2.39	8	6.88	4.26	4	4
Nauseated	59.26	16	5.62	2.78	9	6.25	3.15	10	1
Anxious	22.22	6	5.50	2.59	10	5.67	3.01	14	4
Carefree	48.15	13	5.50	2.81	11	5.67	3.82	15	4
Dizzy	77.78	21	5.43	2.01	12	5.62	3.43	16	4
Wobbly	59.26	16	5.38	2.09	13	6.25	3.44	11	2
Clumsy	62.96	17	5.12	2.29	14	5.76	3.46	12	2
Light-headed	66.67	18	4.78	2.71	15	5.33	4.10	17	2
Drowsy	48.15	13	4.77	2.31	16	6.31	4.50	8	8
Heart rate changes	25.93	7	4.29	2.36	17	5.71	4.82	13	4
Flushed	29.63	8	3.62	2.07	18	4.75	4.65	18	0
Warm	62.96	17	3.53	1.94	19	3.24	2.05	19	0
Stimulated	29.63	8	3.50	1.69	20	3.00	1.51	20	0
Calm	48.15	13	2.92	1.85	21	2.62	1.89	21	0

(B)			Amount of Alcohol (Small [1] to Large [10]) to Experience Effect			Number of Drinks (0–20+) to Experience Effect			Alcohol Abs. Rank Diff.	Amount of Cannabis (Small [1] to Large [10]) to Experience Effect			Number of Hits (0–20+) to Experience Effect			Cannabis Abs. Rank Diff.
Subjective Effects	%	n	M	SD	Rank	M	SD	Rank		M	SD	Rank	M	SD	Rank
Head throbbing	9.72	7	6.14	2.12	1	5.43	1.90	10	9	4.33	2.66	3	2.86	3.39	21	18
Upset stomach	26.39	19	5.63	2.17	2	5.68	2.33	7	5	3.68	2.54	10	3.39	2.68	19	9
Nauseated	45.83	33	5.58	2.35	3	5.42	2.22	11	8	4.38	2.66	2	4.68	2.66	9	7
Impaired vision	43.06	31	5.47	2.16	4	6.87	3.47	3	1	3.29	2.09	14	4.50	3.77	12	2
Numb	29.17	21	5.29	2.35	5	7.38	3.99	1	4	4.40	2.37	1	5.48	3.68	2	1
Slurred speech	48.61	35	5.03	1.96	6	6.94	3.22	2	4	3.17	1.72	19	4.76	3.69	8	11
Wobbly	48.61	35	4.94	2.01	7	5.49	2.58	8	1	3.39	1.77	13	3.94	3.07	18	5
Difficulty thinking	34.72	25	4.92	2.08	8	5.96	3.41	5	3	3.12	1.62	20	4.17	2.99	15	5
Dizzy	54.17	39	4.90	2.10	9	5.21	2.46	12	3	3.95	2.00	6	5.46	3.58	3	3
Clumsy	51.39	37	4.73	1.94	10	6.22	2.77	4	6	3.19	1.66	17	4.28	3.16	14	3
Sluggish	30.56	22	4.65	2.56	11	5.47	2.52	9	2	4.24	2.19	4	5.33	3.29	4	0
Light-headed	51.39	37	4.57	2.18	12	4.57	2.26	17	5	3.72	1.89	8	4.66	2.82	10	2
Heart rate changes	26.39	19	4.33	1.85	13	4.88	2.93	15	2	3.71	1.72	9	4.06	2.77	16	7
Flushed	31.94	23	4.27	1.83	14	5.00	2.41	14	0	3.18	1.65	18	3.14	2.57	20	2
Drowsy	52.78	38	4.13	2.04	15	4.50	2.59	18	3	3.43	1.79	12	4.82	3.56	7	5
Stimulated	31.94	23	4.13	2.10	16	5.00	2.75	13	3	3.26	2.40	16	4.04	3.02	17	1
Breathing changes	22.22	16	4.06	2.11	17	5.81	4.69	6	11	4.12	1.86	5	6.44	3.35	1	4
Warm	56.94	41	3.95	2.07	18	4.18	2.23	19	1	3.08	1.83	21	4.41	3.89	13	8
Carefree	48.61	35	3.94	2.01	19	4.74	3.02	16	3	3.67	1.80	11	4.94	3.27	6	5
Anxious	31.94	23	3.32	2.36	20	3.95	4.13	20	0	3.27	1.61	15	4.64	3.76	11	4
Calm	54.17	39	2.84	1.59	21	2.97	1.88	21	0	3.90	2.16	7	5.10	3.30	5	2

Note. “Rank” corresponds to the highest mean value (1) and lowest mean value (21) for each outcome. Abs. = absolute, Diff. = difference, M = mean, SD = standard deviation.

For participants who reported no lifetime simultaneous use of alcohol and cannabis (i.e., only lifetime alcohol use), they first indicated whether they had ever experienced any of the 21 effects as a result of drinking alcohol. Then, for those effects they reported experiencing in their lifetime, they were asked to indicate the amount of alcohol (1 = small, 10 = large) and the number of drinks they needed to consume to experience each effect (ranging from less than 1 [0] to 20 or more [20]).

For participants who reported lifetime simultaneous use of alcohol and cannabis, they indicated whether they had ever experienced any of the 21 effects as a result of “using alcohol and cannabis at the same time with overlapping effects.” Then, for those simultaneous use effects they reported experiencing in their lifetime, they were asked to (a) separately indicate the amount of alcohol and cannabis (1 = small, 10 = large) they needed to consume at the same time to feel each effect and (b) separately indicate the number of drinks (alcohol) and hits (cannabis) that they typically needed to consume to experience each effect (ranging from less than 1 [0] to 20 or more [20]).

Open-ended questions were used to gather qualitative data on participants’ interpretations of each subjective effect term. Specifically, for all effects participants reported experiencing, regardless of their lifetime simultaneous use, we asked an open-ended item (e.g., What does “nauseated as a result of drinking alcohol” mean to you, in your own words? [alcohol] or What does “nauseated as a result of using alcohol and cannabis at the same time” mean to you, in your own words? [simultaneous use]). This was intended to gauge their interpretation of the given effect and determine if they understood the effect in the way we had intended. Additionally, for those who reported lifetime simultaneous use (i.e., reported they have used alcohol and marijuana at the same time so that their effects overlapped), we also asked: “What does ‘so that their effects overlapped’ mean to you, in your own words?”

Results

Quantitative

Quantitative results are presented in Table 1 for both alcohol (Table 2A) and simultaneous use (Table 2B) subjective effects (results are also visualized in Figures 1–3). Although we report means and standard deviations in the sections that follow, results based on medians are available in Supplemental Table 2 for the interested reader.

Figure 1.

Ranked Subjective Effects Compared Across Alcohol Amount and Number of Drinks in Alcohol Only Group (n=27)

Note. This figure corresponds to Table 2A. “Rank” indicates heaviest mean amount/number of drinks (1) to lowest mean amount/number of drinks (21). Amount = Amount of alcohol (Small [1] to Large [10]) to experience effect. Number = Number of drinks (0–20+) to experience effect.

Figure 3.

Ranked Subjective Effects Compared Across Cannabis Amount and Number of Hits in Simultaneous Use Group (n=72)

Note. This figure corresponds to Table 2B. “Rank” indicates heaviest mean amount/number of hits (1) to lowest mean amount/number of hits (21). Amount = Amount of cannabis (Small [1] to Large [10]) to experience effect. Number = Number of hits (0–20+) to experience effect.

Alcohol.

Of the 27 participants who reported no lifetime simultaneous use, the most common lifetime alcohol-related subjective effect reported was feeling “dizzy” (77.78%, n = 21) and the least reported were “breathing changes” (22.22%, n = 6) and feeling “anxious” (22.22%, n = 6). Breathing changes was consistently the heaviest drinking effect reported for the amount of alcohol (M = 7.00, SD = 3.22) and number of drinks (M = 8.83, SD = 4.96). Feeling “flushed” (M_amount = 3.62, SD = 2.07; M_drinks = 4.75, SD = 4.65), “warm” (M_amount = 3.53, SD = 1.94; M_drinks = 3.24, SD = 2.05), “stimulated” (M_amount = 3.50, SD = 1.69; M_drinks = 3.00, SD = 1.51), and “calm” (M_amount = 2.92, SD = 1.85; M_drinks = 2.62, SD = 1.89) were consistently the lightest drinking effects reported. The ranking of subjective effects across the amount of alcohol and number of drinks reported were relatively similar (M_{difference in ranking} = 2.10; rangedifference in ranking = 0–8) with the largest rank difference between amount and number of drinks being for the effect of feeling “drowsy” (rank difference = 8; M_amount = 4.77, SD = 2.31, rank = 16; M_drinks = 6.31, SD = 4.50, rank = 8) (see Figure 1).

Simultaneous use.

Of the 72 participants who reported lifetime simultaneous use, the most common lifetime simultaneous use subjective effect reported was feeling “warm” (56.94%, n = 41) and the least commonly reported was “head throbbing” (9.72%, n = 7).

For amount/number of alcoholic drinks, there were notable differences across the effects with respect to their rankings. “Head throbbing” was associated with the heaviest amount of alcohol (M_amount = 6.14, SD = 2.12; M_drinks = 5.43, SD = 1.90) but not the largest number of drinks, which was instead associated with feeling “numb” (M_amount = 5.29, SD = 2.35; M_drinks = 7.38, SD = 3.99). Feeling “calm” was associated with both the least amount of alcohol (M = 2.84, SD = 1.59) and the fewest drinks consumed (M = 2.97, SD = 1.88). The ranking of simultaneous use subjective effects across the amount of alcohol and number of drinks reported were relatively similar (M_{difference in ranking} = 3.52, rangedifference in ranking = 0–11). The largest rank difference between amount and number of drinks was the simultaneous use effect of “breathing changes” (rank difference = 11; M_amount = 4.06, SD = 2.11, rank = 17; M_drinks = 5.81, SD = 4.69, rank = 6) (see Figure 2).

Figure 2.

Ranked Subjective Effects Compared Across Alcohol Amount and Number of Drinks in Simultaneous Use Group (n=72)

Note. This figure corresponds to Table 2B. “Rank” indicates heaviest mean amount/number of drinks (1) to lowest mean amount/number of drinks (21). Amount = Amount of alcohol (Small [1] to Large [10]) to experience effect. Number = Number of drinks (0–20+) to experience effect.

For amount/number of hits of cannabis, there were also differences across simultaneous use effects with respect to their rankings. “Numb” was associated with the heaviest amount of cannabis (M_amount = 4.40, SD = 2.37; M_hits = 5.48, SD = 3.68) but not the largest number of hits, which was instead associated with “breathing changes” (M_amount = 4.12, SD = 1.86; M_hits = 6.44, SD = 3.35). Feeling “warm” was associated with the least amount of cannabis (M = 3.08, SD = 1.83), but not least number of hits (M = 4.41, SD = 3.89, rank = 13). In comparison, “head throbbing” was associated with the least number of hits (M = 2.86, SD = 3.39, rank = 21), but not the least amount of cannabis (M = 4.33, SD = 2.66, rank = 3). The ranking of simultaneous use subjective effects across the amount of cannabis and number of hits reported were relatively similar (M_{difference in ranking} = 4.95, rangedifference in ranking = 0–18) with the largest rank difference between amount and number of hits being for the simultaneous use effect of “head throbbing” (rank difference = |18|) (see Figure 3).

Comparing across alcohol and cannabis for simultaneous use subjective effects, the average ranked difference (between amount and number of drinks/hits) range for alcohol is smaller (3.52) than the average ranked difference for cannabis (4.95). When the average ranked difference is compared for alcohol across the alcohol-only (2.10) and simultaneous use (3.52) participants, the average ranked difference across amount and number of drinks is larger for simultaneous use.

Qualitative

The qualitative responses from participants for each effect (e.g., “What does ‘nauseated as a result of drinking alcohol’ mean to you, in your own words?”) offered rich insights into how participants interpreted each alcohol-related and simultaneous use-related subjective effect and whether those interpretations were consistent with the intended meaning. Below we briefly summarize the qualitative responses for participants who reported lifetime alcohol use only and those who reported lifetime simultaneous use. All qualitative responses are presented in Supplemental Tables 3 and 4 (https://osf.io/4kn2f/).

Alcohol.

There were several instances in which there was consensus among participants in terms of the meaning of the effect but the ways in which that effect was described by participants differed. For example, most participants seemed to understand feeling “dizzy” but described the effect using different reference points, with some noting vision changes (e.g., “vision shakey” [participant 32]), others describing a spinning sensation (e.g., “the spins” [participant 69]), and others noting difficulties with walking or balance (e.g., “Not being able to walk straight” [participant 117]). In these instances, participants seemed to understand the effect as intended but had different ways of describing their experience of that effect.

In comparison, there were effects for which participants did not seem to understand the effect as intended. For example, having an “upset stomach” is intended to capture feeling sick or nauseous while drinking. Although the majority of participants interpreted it in this way (e.g., “feel like puking” [participant 97]), others interpreted “upset stomach” as being more related to a next day effect or hangover (e.g., “When I drink more then my usual I get an upset stomach the next day I have to use the bathroom until I feel the alcohol has left my system to feel better” [participant 81]). For feeling “numb”, some participants interpreted this as feeling physically numb (e.g., “My nose and facial features would sometimes feel numb as an indication that I have begun to drink alcohol” [participant 12]) whereas others interpreted it as feeling emotionally numb (e.g., “Not a physical feeling but more of an emotionless feeling” [participant 15]), and one participant interpreted it as both physical and emotional (e.g., “It means that you don’t feel much or anything. For me it’s physically and mentally” [participant 171]).

Simultaneous use.

As with the alcohol-related effects, there were many effects for which there seemed to be consensus among the participants in terms of the meaning of the effect but the ways in which that effect was described differed. For example, most participants seemed to understand the effect of “light headed” but described it in various ways including finding it hard to think or feeling unfocused (e.g., “Light-headed to me means that I am not incoherent but not fully functioning in my reasoning and judgement” [participant 171]), not feeling present (e.g., “like in a daze sort of” [participant 19]), or feeling dizzy or like they might pass out or fall down (e.g., “Kind of the feeling of dizziness or feeling like I’m about to pass out” [participant 18]).

Comparatively, there were effects for which participants did not seem to understand the effect as intended. Feeling “stimulated” was both understood in widely varying ways (e.g., energized, aroused, euphoric, alert) but also in ways that seemed inconsistent with its intended meaning (e.g., “…moods changing” [participant 110] and “…aggressive” [participant 144]). Feeling “flushed” was understood as feeling hot or red (e.g., “my face and hands feel warm” [participant 36], “Flushed is getting red in the face, neck, and chest” [participant 166]) but also misunderstood as feeling tired (e.g., “My body feels drained” [participant 48], “tiredish” [participant 88]), “dizzy” (participant 9), or in a positive mood (e.g., “your face hurts from smiling so much” [participant 83]).

There were instances in which participants explicitly noted certain effects were more common for them with one substance than another or noted specific degrees of the effect depending on the substance. For feeling “warm,” one participant noted, “Warmth in stomach and face from alcohol consumption, worsens with weed use in combination” (participant 47). As another example, one participant noted that “slurred speech” happened more with alcohol (e.g., “I have never slurred my speech when consuming cannabis and will begin to slur my speech after four shots of hard liquor, several beers, or four glasses of wine” [participant 166]) whereas another participant reported, “I can’t speak right when I am Intoxicated or high” (participant 169) when interpreting this effect.

When participants endorsing simultaneous use were asked what the phrase “so that their effects overlapped” meant to them, a large majority described this as meaning “crossed” or “cross-faded.” More specific responses included, for example, “…means that both the side effects from alcohol and the side effects of marijuana happen at the same time. Some of these symptoms cancel each other out and lead to a different and new feeling” (participant 6), “…you are experiencing both a high and a low” (participant 149), “Being high and drunk at the same time” (participant 132), “Alcohol and marijuana have different affects. So when used together I experienced both of their affects and even felt worse because they counteracted each other to produce other affects” (participant 96), and “In my eyes, the effects of alcohol and cannabis are opposites. When put together, the effects overlap and it almost feels as though you have lost all control” (participant 87).

Discussion

The overarching goal of the current mixed-methods study was to conduct an in-depth examination of alcohol-related subjective effects across multiple assessments. We aimed to examine the prevalence of experiencing individual effects, level of use required to achieve specific effects, and interpretations of each effect experienced. Overall, across our two samples of individuals who reported on subjective effects when using only alcohol and individuals who reported on effects when combining alcohol and cannabis, we found that several effects were far more common than others. Our findings also suggested that participants had varied interpretations of each subjective effect and in some cases, participants interpreted an effect in a way that differed from the original intention of the measure. These findings most critically suggest that assessing ‘prevalence’ of subjective effects may be based on a false premise as such potential discrepancies can result in measurement error and can impact reliability and validity of these widely used assessments.

Several noteworthy findings emerged across both samples that have implications for future work. First, breathing changes, heart rate changes, and feeling anxious were least commonly endorsed in our alcohol-only use sample, with approximately only one-quarter or fewer participants indicating having ever experienced these effects. Head throbbing was least commonly endorsed among our simultaneous use sample. Some, such as breathing changes and head throbbing, required the heaviest alcohol and/or cannabis use to experience this effect, which may explain why so few individuals endorsed this item. These findings may have implications when using the Sensation Scale (Adesso & Lauerman, 1975; Maisto et al., 1980) specifically, as several of the less frequently endorsed physical attributes appear on this scale. Second, participants interpreted several effects quite differently, particularly with regard to a physical state or mood state. For example, there appeared to be a divide regarding whether participants interpreted the subjective effect of ‘feeling numb’ as emotionally or physically numb, and feeling ‘light-headed’ was interpreted as feeling unfocused or feeling dizzy. Similar concerns emerged for feeling ‘stimulated’ or ‘flushed.’ As affect and motivations for use are critical (e.g., Cooper et al., 1995) – yet separate – determinants of use behaviors from subjective effects, future work may need to be explicit in differentiating physical effects from mood states. Finally, several participants explicitly noted that certain effects (e.g., warmth, slurred speech) were more pronounced or were experienced differently when combining substances relative to using one substance alone. These findings are consistent with other qualitative work demonstrating some unique or stronger effects that emerge when combining (Abrams et al., 2022; Waddell et al., 2023). Participants appeared to have a clear understanding of the probe ‘using alcohol and cannabis so that their effects overlapped’; together, these findings hold promise for the development of subjective effects for simultaneous use. Although measures of quantity and frequency of simultaneous use have been newly developed (Kolp et al., 2023), a validated measure of subjective effects for simultaneous use is an important and warranted area for future work.

Findings may have key implications for momentary assessment and intervention work aimed at identifying and deploying content when risk for heavy use and harm is greatest. Recent advances in technology have made smartphone data capture and intervention more ubiquitous, affording opportunities to deliver individually tailored intervention content to individuals in moments of highest risk (Nahum-Shani et al., 2018). Although still in its infancy, just-in-time interventions hold promising results for reducing higher-risk substance use behaviors (Carpenter et al., 2020). Features such as speed of intoxication and amount consumed throughout a use episode can serve as a key momentary intervention target (Fairbairn & Kang, 2019; Piasecki, 2019). While such objective measures are highly useful markers of risk, they can be challenged by inaccuracies in self-reported amount of alcohol use and/or delays in alcohol sensors detecting level of intoxication (Karns-Wright et al., 2018) as well as intra-individual variations in the experience of subjective effects across use occasions (Boness & Sher, 2022) and wearable sensors for cannabis use have yet to be developed. The majority of momentary assessments of subjective effects to date have focused on intoxication language including sliders of ‘how intoxicated do you feel’ or ‘how drunk do you feel’ on a two-anchored 0 (completely sober or not at all drunk) to 100 (extremely intoxicated or drunkest I’ve ever felt) metric (e.g., Heinz et al., 2013; Quinn & Fromme, 2012). A four-anchored sliding scale was recently developed by crowd-sourcing contemporary intoxication language among the target sample of young adults (i.e., “How did/do you feel after drinking alcohol?” with four evenly spaced anchors ranging from 0 to 100: slightly buzzed, tipsy/“happy”, drunk, and wasted; Linden-Carmichael et al., 2020). When comparing the standard two-anchored slider to the four-anchored slider in a daily diary study, the four-anchored scale was found to capture greater variation in participants’ self-reported effects (higher means and standard deviations) and greater utility of the anchors to self-report their subjective state (Linden-Carmichael & Calhoun, 2021). By identifying speed of drinking through self-reported subjective states (e.g., rapid changes from buzzed to tipsy) as a cue for later alcohol-related harm (e.g., blackout drinking), this scale could be used to tailor messaging in moments of risk. However, this slider focuses only on intoxication-related language and does not consider other cognitive (e.g., difficulty concentrating) or physical (e.g., nausea) effects of alcohol that could similarly be used to inform momentary intervention. Findings from our study suggest that many of these commonly endorsed subjective effects that occur at varying degrees on the ascending and descending limbs of an alcohol use occasion could be incorporated in momentary surveys and used for early detection and intervention opportunity in riskier alcohol or simultaneous use episodes.

There are several limitations that should be noted. First, our sample was limited to individuals who reported past-year heavy episodic drinking. This sample was selected to provide a broad range of potential subjective effects experienced, but findings may not be as generalizable to individuals who consume lighter amounts of alcohol or to individuals who use only cannabis. To increase generalizability of findings, it would be beneficial for similar qualitative and quantitative work to compare effects across individuals who engage in a wider range of alcohol and/or cannabis use patterns. Second, relatedly, lifetime simultaneous use was assessed to also capture a broad range of subjective effects, but responses may have varied between individuals based on their frequency and recency of simultaneous use experiences. Third, our sample was a small convenience sample of college students from a Hispanic-serving institution; findings may be less applicable to other populations, particularly individuals who hold other racial and ethnic identities, and individuals who have never attended college. A larger assessment across a more diverse sample of young adults with heterogeneous alcohol and simultaneous use patterns would enhance the generalizability of subjective effects. Finally, participants were asked about their “typical” alcohol and cannabis use behaviors. Such retrospective reports may be subject to recall biases and may mask important differences in alcohol sensitivity (Boness & Sher, 2022) and alcohol and/or cannabis tolerance. Relatedly, only number of hits were assessed for cannabis use which may be difficult to quantify for certain types (e.g., cannabis concentrates) or routes of cannabis use (e.g., edibles) and ignores level of potency which may strongly impact level of impairment and effects experienced. We look forward to future work that aims to more precisely account for the interactions between subjective effects and cannabis potency. Limitations notwithstanding, our findings have important methodological implications for assessing alcohol and simultaneous use subjective effects and hold promise for application in momentary assessment and intervention work.

Public Significance Statement:

Alcohol-related subjective effects, or feelings one has when consuming alcohol, are strongly related to alcohol use outcomes but little is known about how participants interpret individual effects on widely used scales. This study evaluated participant interpretations of subjective effects related to alcohol use only as well as alcohol with cannabis use. Results suggest some effects were more common than others and participants had varied interpretations of each subjective effect, which may impact the reliability of assessments.