Introduction

Cannabis is among the most commonly used substances in the U.S., and rates of use have steadily increased over the past decade [1, 2]. As of 2022, among young adults aged 19–30, past month prevalence of cannabis use was the same for men and women, closing a decades-long gap in which men had demonstrated a higher prevalence of past-month use than women. Increasing prevalence of past month cannabis use was also observed in adults aged 35–50, although rates of use in men remained higher relative to women. Past month rates of use have also increased across Black, Hispanic, and non-Hispanic white young adults. Although these groups appeared to use cannabis at a similar rate in 2022, past month use prevalence among Hispanic adults almost doubled from 2021. Daily or near daily use is also increasing and is especially prevalent among young adults (~ 11%) with the highest prevalence among “emerging adults” age 18–24 (~ 18%). This is of particular concern given that this level of frequency is associated with more cannabis-related problems and an increased risk of cannabis use disorder (CUD) [3]. On a positive note, adolescent use has largely remained stable, even in the wake of broadening medical and recreational cannabis legalization and decriminalization [1]. An important factor to consider in relation to increased prevalence rates is the reasons why individuals are using cannabis.

The motivational model of substance use, initially proposed to describe reasons for alcohol use, states substances are used to achieve a certain affect [4,5,6]. The source of the affect change may be internal or external, and the valence may be negatively or positively reinforcing. Thus, reasons someone might use a substance are to cope with a negative mood (internal, negatively reinforcing), to enhance a positive mood (internal, positively reinforcing), to conform with the expectations of peers (external, negatively reinforcing), and for social facilitation (external, positively reinforcing) [4, 5]. Pharmacological differences across substances have important implications for the specific reasons someone might use a particular substance. Thus, in addition to these original four motives, expansion motives (to expand awareness) is a validated subscale which significantly predicted cannabis but not alcohol use [7]. These five motives are typically assessed using the Marijuana Motives Measure (MMM) which has shown significant positive associations with more frequent cannabis use and more use-related problems, including impacts on motivation and productivity as well as cannabis dependence and dependence of other substances such as alcohol [7]. In a recent meta-analytic review, use for coping, enhancement, social, and expansion reasons were associated with more frequent cannabis use, and all five motives were associated with greater cannabis use-related problems, most commonly assessed by the Marijuana Problems Scale [8], across a range of adolescent, undergraduate, community, and veteran samples [9]. The Comprehensive Marijuana Motives Questionnaire (CMMQ) includes assessment of these five motives as well and has also validated several other subscales of motives that, while likely not exclusive to cannabis, provide an extensive list of reasons someone may use cannabis, including for celebration, boredom, or sleep; because it is low risk; or simply because it is available [10]. While both the MMM and CMMQ provide relatively simple assessments of cannabis use motives, neither include items related to medical use. With the broadening legalization of cannabis for medical use at the state level in the U.S. and federally in Canada and other countries, as well as a growing body of research on the therapeutic uses of cannabis for certain medical conditions, use for medical or “health” related reasons is also highly relevant [11].

Motives, especially to cope with negative affect, are robust proximal indicators of use and related problems [6, 9]. That is, having more and varied reasons for using is a strong marker of a higher frequency of use, and some motives in particular, such as coping with negative affect, point to more problematic use [12]. Thus, better understanding why an individual uses cannabis has clear implications for prevention and intervention approaches, and, in the case of medical cannabis, the treatment of medical and other mental health conditions and policy related to medical cannabis. The aim of this narrative review is to provide a summary of recent research on cannabis use motives. We searched PsycINFO, PubMed/Medline, and CINAHL databases using search terms that included variations of “cannabis” and “marijuana,” as well as variations of “reasons” and “motives” to capture as broad a literature as possible between 2017 and 2023. We present our findings based on the relative density of the research over the past five years on different motives or reasons for use stemming from the motivational model, followed by medical and health related reasons. Much of the research on reasons for cannabis use has utilized measures derived, at least in part, from the motivational model [7, 10]; therefore, aside from medical reasons, our findings are organized by motives defined by the motivational model. This review focuses on the role of motives on cannabis use and problems and on characteristics of individuals endorsing certain types of motives. See Table 1 for a visual summary. We conclude with a brief discussion on implications for practice and future research.

Table 1 Summary of population and sociodemographic factors and their relationship with different cannabis use motives
Full size table

Research on Coping Motives

Relative to other cannabis use motives, coping motives, or using to avoid or escape adverse psychological states such as negative or unpleasant emotions, have been consistently linked to elevated use and related problems [5, 7, 9]. Multiple studies have identified coping motives as a significant mediator of the relation between depressive and anxiety symptoms (including social anxiety) and cannabis use, consequences, and CUD symptoms [13,14,15,16,17]. One study demonstrated elevated depressive and anxiety symptoms were associated with greater risk of consequences and CUD via greater coping motives leading to increased use [15]. Emotion dysregulation, perceived distress tolerance, and childhood traumatic experiences have also demonstrated indirect effects via coping motives on cannabis use and problems, as well as craving and withdrawal [18,19,20,21]. To highlight the robustness of these relations, these findings are not unique to cannabis and have been observed for alcohol coping motives, use, and problems as well, signaling the importance of assessing for motives related to coping across substances [13, 17, 19].

Coping Motives in Minoritized Groups

Recent research on coping motives highlights the role of belonging to a minoritized group and minority stress on coping-related reasons for cannabis use (see Table 1). Recent research on coping-motivated cannabis use has focused most frequently on Black/African Americans and sexual minority women and gender diverse people. This is perhaps, in part, a reflection of the larger sociopolitical climate. For example, there is evidence to suggest that significant psychological distress, particularly in 2020, a year of considerable turmoil, was associated with increased cannabis use frequency in U.S. adults [22].

The minority stress theory proposes individuals belonging to minoritized racial, ethnic, sexual, and gender identity groups have an elevated risk for substance use and use disorders because of the stress related to belonging to a minoritized group in the U.S., on top of general stressors experienced, and that this elevated risk stems from the depletion or lack of other, substance-free coping resources [23, 24]. Microaggressions and other forms of perceived racial discrimination, subtle or blatant, are stressors unique to minoritized groups, and have demonstrated associations with elevated negative affect and subsequent coping motives predicting cannabis use and related problems [25, 26]. Depressive symptomatology, one form of negative affect, is strongly associated with coping motivated cannabis use and past year use frequency among Black/African American adolescents and emerging adults [14]. A recent study of Black undergraduate students attending a predominantly white institution found that distressed coping motives fully mediated the relation between subtle perceived racial discrimination (e.g., microaggressions) and cannabis use [26]. Additionally, American Indian youth endorse greater cannabis coping motives relative to their white peers, which may also be associated with experiences of discrimination, though more research is needed to clarify this relationship [27]. Considerably more research is also necessary to assess the prevalence of cannabis use motives across racial and ethnic minority groups, and to determine what internal and external factors predict motives for use and how these motives influence use patterns and related problems to better inform and tailor prevention and treatment interventions [28].

Sexual minority (SM) (e.g., lesbian, gay, bisexual) individuals have an elevated risk for developing CUD [29,30,31]. Recent research, predominantly conducted with SM women, has also found associations between minoritized group status, stigma, cannabis coping motives, and cannabis outcomes. An ecological momentary assessment (EMA) study of sexual minority women and gender diverse people found enacted stigma increased the likelihood of cannabis use among those who endorsed greater coping motives and that higher cannabis consumption and intoxication occurred on days when coping motives were reported [32, 33]. Enacted stigma also predicted an increase in cannabis coping motives and subsequent problematic use over time among Bi + emerging adults assigned female at birth [34]. In a study of Black undergraduate students at a predominantly white institution, those who identified as a SM reported greater cannabis use frequency and consequences relative to straight/heterosexual peers, and coping motives mediated the association between SM status and cannabis use frequency [35]. Further, cannabis disparities for SM individuals widened during the COVID-19 pandemic. Greater cannabis use frequency, consequences, and coping motives were observed among SM individuals during the pandemic relative to non-SM individuals independent of pre-pandemic levels, and coping motives predicted cannabis use and consequences in SM individuals but not in non-SM individuals [36].

Altogether, coping motives for cannabis use remain a robust indicator of cannabis use and related problems. It will be critical for prevention and treatment intervention efforts to target coping motives, alternatively teaching skills, providing more substance-free resources to help manage negative affect, and addressing mental health symptoms early to help prevent the onset of use [37]. Understanding the source of negative affect (e.g., perceived racial discrimination), especially in individuals identifying as belonging to minoritized groups, and its role in coping motivated use will be crucial to developing efficacious targeted interventions.

Research on Enhancement, Social, Expansion, and Conformity Motives

Enhancement/Enjoyment

People are often motivated to use substances such as cannabis as a method of enhancing positive experiences that may arise as a result of intoxication [7]. Perhaps unsurprisingly, those with a greater number of substance-using peers are more likely to report enhancement motives, and enhancement motives are endorsed more often on the weekend, as well as on days when people report greater use [14, 33, 38]. Importantly, only weekend enhancement motives were associated with cannabis-related problems, suggesting that a subset of people may seek enjoyment from cannabis use at the expense of other, possibly more important or meaningful, activities on the weekend. While this reason for use is common, prevalence of enhancement motives may vary according to sociocultural factors. Similar to coping motivated use among Black/African American sexual minority individuals, enhancement motives were also more likely in this group relative to heterosexual/straight individuals; however, enhancement motivated use was not associated with greater cannabis use frequency, highlighting some differential patterns of use related to different motives [35].

Broadly, enhancement/enjoyment motives are associated with greater cannabis use and adverse health outcomes [32, 39,40,41]. Among a Canadian cohort of community adults, greater cannabis use was associated with greater endorsement of enhancement motives, regardless of sociodemographic factors. Interestingly, enhancement motives have been found to predict more problematic use according to the Cannabis Use Disorders Identification Test–Revised (CUDIT-R), but not DSM-5 criteria, suggesting that problems associated with greater enhancement motivated use are subthreshold of a use disorder [40]. This could signal a point for implementation of early intervention. As a mediator between mental health problems and cannabis use and related problems, the role enhancement motives plays is unclear (see Table 1). Some research indicates there is a negative relationship between depressive symptoms and enhancement motives, with one study demonstrating that this, in turn, was associated with lower cannabis use and related harms [42, 43]. While this may suggest a potential protective effect, another study found positive associations, suggesting that those with depression may use cannabis to experience pleasure, resulting in greater use related problems [16]. Clearly, this area warrants considerably more research, with one potential focus to discern the role of enhancement motives on cannabis use and problems trajectories and how it may be leveraged in the design of prevention and intervention programs.

Social Motives

Similar to enhancement motives, social motives typically stem from an individual’s desire to have a positive experience [7]. Key hallmarks of social use motives include the desire to “celebrate a special occasion with friends” or because it “makes social gatherings more fun.” Relative to coping and enhancement motives, social motives have been inconsistently linked to cannabis use frequency and harms, with some studies finding positive associations with cannabis outcomes and others finding no relation [6, 14, 16, 44, 45]. Similar to coping and enhancement motives, evidence indicates social motives are common among minoritized groups. Among sexual minority women and gender diverse individuals, endorsing social motives was associated with more same-day cannabis use and consequences, and these relationships were moderated by typical use frequency [33]. Alternatively, while social motives were among the most frequently endorsed motives in a sample of Black/African American adolescents and emerging adults after enhancement motives, they were not associated with more frequent use [14]. More research is necessary to better understand social motives for cannabis use and the circumstances under which they may predict cannabis use related harms.

Expansion Motives

While the previously discussed motives originated from alcohol research, expansion was introduced as an explanation for cannabis and other psychedelic type substances [7]. Expansion represents a motivation for seeking expanded experiential awareness, characterized by items such as, “I use cannabis so I can know myself better” or “…it helps me be more creative and original.” Although expansion is less commonly reported compared to other motives, it may be more frequently endorsed by men compared to women, as well as sexual minority individuals relative to straight individuals [35, 38, 39, 46]. Evidence from a meta-analysis, a daily diary study, and a longitudinal study indicate that expansion motives are consistently associated with cannabis use frequency, but not cannabis related problems [9, 46, 47]. However, among college students reporting past month cannabis and alcohol use, stress, anxiety, and depression were positively related to cannabis use quantity and negative consequences via expansion motives [42]. Additionally, research has found expansion motives to moderate the relationship between stress and anxiety, such that the association between stress and anxiety grew stronger as expansion motives increased, suggesting that use for expansion reasons may exacerbate negative affective symptoms [48]. In general, expansion motives appear to be positively related to cannabis use frequency, however, its contribution to cannabis-related harms is less clear or consistent, and, in light of growing evidence that expansion motives may be implicated in developing negative affective symptoms, further research is necessary.

Conformity Motives

Conformity motives for cannabis include using “because my friends pressure me to use marijuana,” “to be liked,” and “so I won’t feel left out” [7]. Similar to expansion motives, significantly less research has focused on conformity motives. This may be due to inconsistent findings from earlier studies either failing to demonstrate an association between conformity motives and cannabis use frequency or finding a negative association [49,50,51]. Further, a recent meta-analytic review of 48 studies found significant positive correlations between cannabis use frequency and all motives except for conformity [9]. Among specific population groups, a negative association is seen for conformity motives. For example, in a sample of Black/African American adolescents conformity motives predicted less past-12 month cannabis use [14]. In contrast, one study involving predominantly white female college students found conformity motives to be positively predictive of scores on the CUDIT-R screening tool [40].

Despite the majority of findings from recent studies, conformity motives may play an important role in the context of mental health concerns, particularly anxiety. Among college students who use cannabis, conformity motives were found to significantly moderate the association between stress and anxiety, and in the opposite direction between anxiety and stress, thus suggesting a bi-directional relationship in which the strength of this relationship is increased when individuals’ use is motivated by a desire mitigate external pressure to use [48]. Perhaps unsurprisingly, conformity motives have also been found to moderate the relationship between social anxiety and behavioral willingness to use cannabis [52]. Although research on conformity motives as a moderator of mental health concerns is sparse, these recent findings suggest that individuals with elevated stress or anxiety, specifically social anxiety, may benefit from interventions targeting conformity motives as well as coping motives as highlighted previously.

Research on Medical Use Motives

There is sufficient research evidence to support the use of medical cannabis (typically low concentration of Δ9-tetrahydrocannabinol, THC; higher in concentration of cannabidiol, CBD) for symptom management of certain medical conditions, including chronic pain and multiple sclerosis (MS), and often successfully used for its anti-emetic properties in cancer patients undergoing chemotherapy [11, 53, 54]. However, in states that have legalized the medical use of cannabis, there are several qualifying conditions (varying by state) for which a physician may verify the use of medical cannabis that are not sufficiently supported by research. In some states, it is up to the physician’s discretion as to what medical conditions are “qualifying” and may not be listed under the state’s law [53].

Research on motives for medical cannabis (MC) use has increased rapidly in recent years. The most frequently cited reasons for MC use were to manage chronic pain and/or other chronic conditions such as glaucoma, cancer, and HIV/AIDS, followed by to help with sleep [15, 55,56,57,58,59,60,61,62,63,64]. However, not all cited reasons are for medical conditions or supported by evidence-based research. For example, there is evidence indicating that cannabis may actually disrupt circadian rhythms, thereby negatively impacting sleep [11, 53, 65]. Similarly, a large study of individuals across the U.S. and Canada (N = 27,169) assessed self-reported physical health reasons for medical cannabis use, finding headaches/migraines, appetite, and nausea/vomiting, in addition to pain management and sleep, to be the most common, and self-reported mental health reasons, finding anxiety, depression, and posttraumatic stress disorder (PTSD)/trauma, as well as managing other drug or alcohol use and psychosis, to be the most common [58]. Similar to pain management, MC seems to be useful in improving appetite and alleviating nausea/vomiting as it is indicated for individuals with wasting disease as a result of HIV/AIDS and as an anti-emetic option for individuals undergoing chemotherapy [11]. However, there is limited or insufficient evidence to support cannabis use for mental health symptoms, which can include appetite or weight loss, or psychiatric disorders [54, 66]. Alternatively, some recent research suggests MC use may be protective against heavier alcohol use, and possibly other drug use and use disorders [67,68,69]. Overall, although chronic pain is the most commonly cited reason for MC use and has the most evidence-based support, many people report using cannabis for health-related reasons that are not supported by research.

Medical Motives Across Age Groups

Approximately 25% of adolescents and adults (18 +) across the U.S. and Canada who use cannabis self-report ever using cannabis for medical reasons [58, 70]. As noted in Table 1, although some research has observed a higher prevalence of use for medical reasons in young adults (26–35 years) [58], other evidence suggests that adults who use for medical reasons were more likely to be over age 45 [56, 71]. Notably, older adult populations (51 +) were more likely to report MC use, specifically for chronic pain and other chronic or somatic conditions [56, 71], whereas adolescents (14–17) and young adults (18–30) report MC use when bored or for health reasons not necessarily related to a medical condition (e.g., to improve sleep, energy, appetite) [39, 56, 72], suggesting there could be age-related factors moderating cannabis use motives. There is also some incongruent evidence by sex/gender. In some cases, men were more likely to self-report cannabis use for medical reasons, whereas in others, individuals who use for medical reasons, or both medical and recreational, were more likely to be women [58, 63, 71, 73]. It is not entirely clear why these incongruencies exist. A number of factors could explain these disparate findings including sampling and data collection procedures and/or how MC use was defined by researchers. There could also be differing perceptions as to what MC use is as a function of sex/gender. For example, men and women tended to report different symptoms or conditions for which they use MC, with men reporting use for cancer, bipolar disorder, and problems related to alcohol or other drug use, and women reporting use for sleep, headaches/migraines, and anxiety [58]. Thus, depending on the sampling procedures and the definition of MC used in a study, incongruencies could arise in terms of who is more or less likely to endorse medical reasons for cannabis use or use of MC.

People reporting MC use appear to meet CUD criteria at similar or slightly higher rates relative to those in the broader population of people who use cannabis recreationally [74], and cannabis problems are positively associated with a number of non-medical use motives among MC patients, such as use for enjoyment, coping reasons, boredom, and social anxiety [75]. The effect of medical motives on cannabis use and problems appears to be largely dependent on the types of endorsed medical or health related motives for cannabis use and age-related factors. A recent meta-analysis of MC studies observed more problematic use of medicinal cannabis in younger populations (18–29) and a greater likelihood of CUD in individuals with worse mental health (e.g., depression, posttraumatic stress disorder, psychotic disorders, and other SUDs) [74]. Regarding age-related factors, younger MC patients (18–30) have reported higher quantities of use and higher rates of problematic use relative to middle-age (31–50) and older patients (51 +) [56]. Among 9th-12th graders in Ontario, Canada, relative to non-medical use, MC use was associated with several risk factors including more frequent cannabis use, greater risk for cannabis dependence, a higher likelihood of using tobacco and recreational use of other drugs, and a lower likelihood of reporting good health and adequate sleep [70]. In a sample of French high school students, “health” motives (e.g., to improve sleep, form, energy, appetite, health) were a strong predictor of use frequency and problematic use, and in a sample of French college/university students, they were the strongest predictor of CUD relative to all other motives (e.g., coping, enhancement) [39, 72]. Indeed, self-medicating with cannabis among young adults appears to be widespread and for reasons that are indicative of more substantial problems [76].

In addition to being associated with use patterns and problems, health-related reasons may also drive selection of cannabis products. For example, endorsement of use motives significantly differed by oral cannabis product use and individuals endorsing medical cannabis use report greater use of non-combustible cannabis products [77, 78]. Furthermore, use motives may be related to selection of products based on cannabinoid content. THC and CBD have different pharmacological and subjective effects; people rate products containing CBD as being more therapeutic than THC only products [79].

Across all age groups, perceptions of medical reasons for cannabis use seem to be quite broad and do not necessarily consider the quality or availability of evidence for the efficacy of MC for medical conditions and health-related symptoms. Implications for use patterns and the risk of developing CUD are evident. More research on conditions that MC can be considered an evidence-based treatment for is critical for defining “qualifying” conditions as well as for providing clear education and guidance for patients and providers to prevent use that could result in problems, e.g., CUD. Further, terminology should be made clear regarding “use of medical cannabis” prescribed by a physician for evidence-supported conditions, vs. “use of cannabis for medical/health reasons,” the latter of which seems more subject to individual judgment.

Conclusions and Implications for Practice, Policy, and Future Research

Motives are robust proximal indicators of cannabis use and, in some cases, related problems (e.g., CUD). Recent research on cannabis use motives highlights an important distinction to be made between use for evidence-based medical conditions (e.g., chronic pain management) and use for “health reasons,” either physical or psychological (e.g., depression, anxiety). Indeed, coping motives comes from the motivational model and is characterized by use to manage adverse psychological states [7]. It is possible that individuals who use to manage physical symptoms may be likely to also use to manage psychological symptoms; however, limited research on this topic exists. Research to distinguish domains of motives to manage adverse experiences is urgently needed. Further, this distinction may be especially important for adolescents and young adults who are more likely to report use for “health reasons,” given that these have stronger associations with increased cannabis-related problems. However, it is important to acknowledge the cannabis use motives literature for adults (broadly defined as age 25 +) is limited compared to that of younger populations. With the ever-broadening legalization of medical and recreational cannabis, prevention and early interventions may benefit from an informed and collaborative discussion of the reasons youth are using cannabis and the difference between use for evidence-based medical conditions and use for “health reasons” and self-medication.

Although medical cannabis plays a critical role in the symptom management of certain medical conditions, decreasing perceptions of risk and inconsistent medical cannabis policies by state in the U.S. may contribute to conflating use for evidence-based medical conditions with use for any physical or mental health-related reasons despite a lack of sufficient evidence [1, 11, 53, 66]. In terms of medical cannabis related policy, while a federal level policy could provide the most clarity and consistency, at minimum, states should work collaboratively to design policies that are consistent with available medical research and align with policies and procedures in other states, especially on the designation of “qualifying” conditions. Consistency across the U.S., and globally, lends itself to clearer messaging regarding the use of medical cannabis. Additionally, healthcare providers and healthcare systems can also play an important role in reducing harms associated with use of cannabis for medical and non-medical reasons by following the Screening, Brief Intervention, and Referral to Treatment (SBIRT) stepped-care approach [80]. Incorporating a rapid assessment of reasons for cannabis use within the screening or brief intervention portion can provide some insight into the level of risk and the focus of the brief intervention or referral to treatment required to minimize risk.

Further, to maximize the potential benefits of the therapeutic use of medical cannabis and minimize harms associated with “self-medicating” or “off-label” use, it is necessary to determine how different reasons for use influence how an individual uses cannabis, beyond use frequency alone, and whether this manner of use predicts problems. One avenue may be examining the selection of cannabis products (e.g., combustible, edibles, oils/concentrates) and reasons for use. Cannabis products vary considerably in their cannabinoid composition (e.g., THC and CBD) and reasons for use may not only drive use frequency/quantity, but also selection of products which in turn could have an important impact on cannabis-related harm. As we are familiar with only one study that specifically examines perceptions of cannabis by cannabinoid content [79], this is an important aspect for future study, which in turn will be critical to informing intervention and policy.

In addition, while recent research on cannabis use motives has extended somewhat to older age groups, the predominant focus of this research remains within younger demographics. Research on cannabis use motives in middle-age (31–50) and older adult (51 +) populations has, understandably, primarily focused on medical-related motives; however, motives for use do not occur in a vacuum and often individuals use for various intersecting reasons that change over time [50]. With significant increases in past month cannabis use among middle-age and older adults, additional work is needed to understand the course of cannabis motives in relation to use beyond young adulthood [81]. Further, qualitative research among older adults suggests there may be an immediate need for educational resources on this topic for this particular age group and physicians treating them [59, 62]. Finally, recent research also highlights the need for continued exploration on how intersecting identities and experiences related to age, sex and gender, sexual minority status, and race and ethnicity are associated with motives for cannabis use and cannabis use outcomes.

Despite a relatively extensive literature on cannabis use motives, rapidly changing policies and perspectives on cannabis use are raising important questions regarding why and how people use cannabis, particularly in regard to its medical use (see also the discussion in Dawson et al. [74]). Recent research demonstrates that this can have significant impacts on cannabis and other health related outcomes and that important age, sex/gender, sexual minority, and racial/ethnic background related differences exist. Clarity in how motives develop and change over time across demographic groups is also critical for targeted prevention and treatment intervention efforts. Continued research is necessary to better inform policy and clinical practice.