Bisexuality and Substance Use

This article highlights an urgent need to better understand the substance use disparities affecting bisexual people. The National Institutes of Health (NIH) and the National Academy of Medicine (NAM) have made calls for research to identify risk factors for adverse health outcomes, including substance use behaviors, among bisexual people. Despite growing interest in this area, our understanding of why bisexual people are at increased risk for substance use remains limited. Today, an increasing percent of the U.S. population identifies as bisexual. The literature consistently shows higher rates of substance use and resulting consequences among bisexual people relative to both heterosexual and gay/lesbian people. Thus, it seems an opportune time to review research on substance use in bisexual populations. In this article, we review this literature and identify important findings in several key areas to guide future work including heterogeneity in substance use, distal and proximal risk factors, and intersectional forces that influence elevated substance use patterns among bisexual individuals.


Introduction
Bisexual people remain one of the most overlooked sexual minority populations despite the fact that they are at high risk for substance use and other adverse health outcomes. Of note, bisexual individuals are not inherently at higher risk for such concerns but rather their vulnerability is heighted due to minority stressors related to their sexual orientation (e.g., heterosexism, monosexism) and other marginalized identities (e.g., racism) as well as other risk factors. Today, a growing proportion of the U.S. population identifies as bisexual [1,2]. Until recently, sexual and gender minority (SGM) research has largely looked at SGM individuals as a monolith instead of distinct population groups each with their own set of specific health needs. The National Institutes of Health's (NIH) definition of SGM is as follows: "an umbrella term that encompasses lesbian, gay, bisexual, and transgender populations as well as those whose sexual orientation, gender identity/expressions or reproductive development varies from traditional, societal, cultural, or physiological norms" [3]. In 2011, the NIH formally designated SGM people as a health disparity population [4,5].
The NIH and the National Academy of Medicine (NAM) have made calls for research to identify risk factors for adverse health outcomes, including substance use behaviors, among bisexual people [5,6]. Despite these calls to action, the SGM population is often still combined as a single entity, limiting research on and attention to bisexual people's health specifically. Moreover, while there have been increases overall in research focused on the health of SGM people, there has been a notable lack of research focused on bisexual individuals, even though bisexual people make up the largest proportion of the SGM population [7]. Mounting evidence highlights mental, physical, and other health disparities among bisexual individuals [8 •, 9•, 10, 11]. As a result, in August 2022, the NIH published a Notice of Special Interest emphasizing the need for increased consideration of bisexual populations in research, including on substance use behaviors [12].
Historically, SGM individuals report higher rates of substance use than heterosexual individuals [13]. The high prevalence of substance use among SGM people has been attributed to the unique stressors they experience rooted in societal stigma including distal stressors (e.g., discrimination, victimization) as well as proximal stressors (e.g., internalized stigma, anticipated rejection) [14•]. However, the act of dichotomizing sexual orientation into two groups-either heterosexual or non-heterosexual-obscures the rates of substance use that are variable among distinct sexual orientation subgroups [15]. When researchers have separated gay/lesbian and bisexual individuals in their analyses, findings have consistently shown that bisexual individuals report higher substance use compared to monosexual (i.e., heterosexual, lesbian, and gay) individuals [8•, 9•]. For instance, recent studies show that alcohol use, cigarette smoking, and illicit drug use are more prevalent among bisexual people than gay/lesbian and heterosexual people [8•, 9•, 16-19]. To better understand some of these trends, this review evaluates recent empirical evidence on elevated substance use patterns among bisexual individuals, with a specific focus on heterogeneity in substance use disparities (e.g., based on the type of substance, timeframe, and the dimension of sexual orientation), distal and proximal risk factors, and intersectional forces that influence elevated substance use patterns among bisexual individuals with additional minoritized identities (e.g., bisexual people of color).
Given the growing interest in bisexual people's health, it seems an opportune time to review findings on bisexuality and substance use. To provide a synopsis of current information, our review focuses on research from the past 5 years. However, we also include other important studies that are older than this. The majority of the articles referenced here are from U.S. samples. Although this is not a systematic review, we emphasize interesting and important findings with an aim to bring readers up-to-date on the subject. We use the term bisexual to include both self-identified bisexual people as well as those who report attraction to more than one gender and/or sexual behavior with partners of more than one gender. We also want to acknowledge people who use other labels to describe multi-gender attractions (e.g., pansexual, queer, fluid) [20,21]. Thus, our review focuses on bisexual people, but at times refers to bi+ people as an umbrella for people who use different labels to describe multi-gender attractions. 1

Heterogeneity in Substance Use
As referenced above, previous reviews have concluded that bisexual people are generally at increased risk for substance use and disorders compared to monosexual people. While these disparities have been documented across multiple substances, there are differences in disparities based on the type of substance, the timeframe (e.g., current vs. past year vs. lifetime), and the dimension of sexual orientation (e.g., identity vs. attraction vs. behavior).
We will begin with alcohol use. Research, including meta-analyses, consistently shows more alcohol use, heavy episodic drinking (HED), and alcohol dependence among bisexual people compared to both heterosexual and gay/lesbian people [17,[22][23][24][25]. A meta-analysis by Shokoohi et al. shows that across all genders, sexual orientation dimensions, and age groups, bisexual individuals have the highest prevalence of lifetime alcohol use as well as past-year and past-month HED [9•]. For instance, bisexual people have 1.18 and 1.25 times the odds of past-year and past-month HED, respectively, compared to gay/lesbian individuals, and 1.70 and 1.51 times the odds of past-year and past-month HED, respectively, relative to heterosexual people [9•]. Bisexual women in particular have elevated odds of pastmonth alcohol use compared to lesbian and heterosexual women [9•]. Interestingly, bisexual men exhibit higher odds of past-month alcohol use compared to heterosexual men, but they exhibit lower odds compared to gay men. However, McCabe and colleagues (2009) find that alcohol dependence in the past year is higher among bisexual men compared to both gay and heterosexual men [17]. Of note, rates of alcohol dependence and other drug use/dependence also tend to be higher for men who have sex with men and women compared to men who have sex with men only [8•, 9•]. For example, men who have sex with men and women are more likely to binge drink than men who have sex with men only (54.5% vs. 35.8%), although their rate was similar to men who have sex with women only (58.0%) [9•].
Beyond alcohol use, research has documented higher rates of cigarette use among bisexual individuals compared to monosexual individuals. A recent meta-analysis by Shokoohi et al. (2021), for instance, demonstrates that bisexual people are at higher risk for lifetime, past 30-day, and current cigarette use [8 •], compared to heterosexual and gay/lesbian people. Shokoohi et al. (2021) shows that bisexual individuals were 2.26 times more likely to report lifetime cigarette smoking, 2.49 times more likely to report past 30-day cigarette smoking, and 2.18 times more likely to report current cigarette smoking than heterosexual individuals [8•]. Relative to their gay/lesbian counterparts, bisexual individuals were 1.19 times more likely to report lifetime cigarette smoking, 1.17 times more likely to report 1 3 past 30-day cigarette smoking, and 1.25 times more likely to report current cigarette smoking. For lifetime, past 30-day, and current cigarette use, results show differential risk of cigarette smoking between genders, as bisexual women exhibited higher rates compared to bisexual men [8•]. Emerging research also shows that bisexual individuals have higher rates of e-cigarette use in terms of prior use and past 30-day use compared to heterosexual individuals [18].
Bisexual people also experience disparities in other drug use (i.e., marijuana, illicit, and prescription drug use) as well as polysubstance use [19,[22][23][24]. Research shows, for instance, that bisexual individuals are 2-3 times more likely to report marijuana use compared to heterosexual individuals [22,23].  found that bisexual men were more likely to report weekly marijuana use than gay men [26]. However, a recent study examining national trends in substance use across sexual identity subgroups found instead that gay men have elevated rates of marijuana use compared to both bisexual and heterosexual men [22]. Of note, this study did not examine weekly marijuana use. Schuler et al.
(2020) assessed general substance use patterns in bisexual women; results showed greater odds of marijuana use, illicit drug use, and opioid misuse compared to lesbian and heterosexual women [23]. This study also found that bisexual and gay men have elevated rates of marijuana and illicit drug use compared to heterosexual men; however, no significant differences were found between bisexual and gay men [23]. In another study, it was found that bisexual individuals were the highest-risk sexual orientation subgroup for all substance use outcomes and had over 8 times the odds of cannabis use compared to heterosexual individuals [18]. Finally, McCabe et al. (2022) show that bisexual women's past-year illicit drug use rates were higher than heterosexual and lesbian women while bisexual and gay men have similarly elevated rates of past-year illicit drug use relative to heterosexual men [22]. Moreover, polysubstance use was most prevalent in bisexual individuals compared to their monosexual counterparts with one in three bisexual women (33.1%) and one in four bisexual men (26.4%) reporting polysubstance use [22].
Research also suggests that bisexual people have greater odds of prescription opioid misuse compared with heterosexual people [24]. For example, a 2019 study found that bisexual men (and gay men) had elevated rates of prescription opioid misuse relative to heterosexual men; rates of heroin use were also higher for bisexual men (however not gay men) relative to heterosexual men [27]. Bisexual women also reported higher rates of lifetime prescription opioid misuse, lifetime injection and non-injection heroin use, past-year opioid misuse, and opioid use disorder relative to lesbian and heterosexual women [27].
Furthermore, bisexual people are at increased risk for substance use before sex. Research shows that bisexual men are twice as likely to use marijuana before sex as gay men [26]. Moreover, among bisexual men, alcohol and marijuana uses before sex are more common with female partners than with male partners, although both are associated with condomless sex [23]. In a sample of gay and bisexual men with histories of childhood sexual abuse and recent sexual risk behavior, Batchelder et al. (2021) found that bisexual men were at higher risk for stimulant use disorder than gay men, even after accounting for the other demographic characteristics [28]. Additionally, bisexual individuals had higher rates of regular sex-related substance use compared to other sexual minority subgroups [14•]. As a result, they were at increased risk for adverse health consequences associated with regular sex-related substance use (e.g., HIV/STI transmission) [15].
In sum, while individual studies differ in the types of substances studied and the magnitude of disparities observed, on the whole, the available data tell us that (1) bisexual people experience disparities across a variety of substances, and (2) they are almost always at higher risk for substance use than heterosexual people and often at higher risk than gay/ lesbian people. Notably, disparities in substance use tend to be larger for bisexual women (compared to bisexual men) [9 •, 22, 26, 27]. Of note, while this review specifically focuses on substance use patterns among bisexual people, evidence also suggests that "mostly heterosexual" individuals report more substance use (tobacco, alcohol, marijuana, and other illicit drugs) compared to exclusively heterosexual individuals [29].

Distal and Proximal Risk Factors
Sexual minorities are disproportionally affected by poor physical and mental health [11,24,26,30,31]. The minority stress framework posits that these poor health outcomes result from the added stress that sexual minorities experience as a result of stigmatization [31]. Studies employing this framework show how bisexual people experience and react to unique stressors resulting from the heightened stigmatization of their sexual orientation [16]. Research shows that both distal (e.g., binegativity, discrimination) and proximal minority stressors (e.g., internalized stigma, expectations of rejection, identity concealment) are highly prevalent among bisexual individuals and are linked to substance use and dependence as well as other adverse health outcomes including anxiety, depression, suicidality, and HIV/STI [11,24,26,30].
In terms of distal risk factors, research shows that binegativity (i.e., negative attitudes toward and treatment of bisexual people) and monosexism (i.e., the belief that everyone is, or should be, monosexual) are associated with more substance use and problems among bisexual people [31][32][33]. For example, binegativity has been shown to contribute to alcohol-related problems; Kelley et al. (2018) demonstrated a trajectory of increasing risk where more experiences of binegativity were associated with greater drinking to cope motives and alcohol consumption [34]. In 2022, Schulz et al. revisited this model, showing that among bisexual women, binegativity was associated with more alcohol-related problems through greater drinking to cope motives and elevated alcohol consumption [35]. Monosexism has been associated with more substance use and problems for white bisexual people assigned female at birth [36]. Moreover, when bisexual people assigned female at birth experienced more enacted bisexual stigma, they reported a greater motivation to use marijuana to cope, which in turn predicted an increase in problematic marijuana use [36].
Bisexual individuals also consistently report less social support than both heterosexual and gay/lesbian individuals [37]. Research shows that social belonging, safety, and support are all important predictors of substance use [16,20,38]. In general, bisexual people report less connection to the lesbian, gay, bisexual, transgender, and queer (LGBTQ +) community compared to gay and lesbian people, which has detrimental effects in terms of belonging [20,37]. Yet, greater LGBTQ + community involvement is not always protective. In fact, among bisexual women, more involvement with the LGBTQ + community has been associated with higher levels of drug use, but this was not the case for lesbian women [16]. This positive association was accounted for by more frequent discrimination, suggesting that biphobia may be problematic within the LGBTQ + community. Of note, Feinstein, Bird, et al. (2017) found that bisexual women reported less frequent drinking in locations with more LGBTQ + people than did lesbian women [16], highlighting the need for more research exploring how influences on social substance use experiences may differ for bisexual vs. lesbian women.
Moreover, being in a relationship may also increase the risk of substance use among bisexual people. In a daily diary study, Vilkin et al. (2022) show that being in a relationship is associated with higher levels of mean daily alcohol use among bi+ people [39]. Relationship involvement is also linked to more marijuana and illicit drug use for bisexual youth (age [16][17][18][19][20], whereas it is associated with decreases in illicit drug use for gay and lesbian youth (Note: study included 20 transgender individuals) [40]. Bisexual women in relationships with men report more binge drinking and alcohol-related consequences than those in relationships with women, and bisexual women with multiple partners report more alcohol-related consequences than those with one partner [41].
In terms of proximal risk factors, internalized stigma, expectations of rejection, and concealment are linked to bisexual people's substance use. Research shows both internalized and anticipated stigma elevate the risk of substance use among bisexual people [36]. For example, one meta-analysis found a positive relationship between internalized heterosexism and alcohol, tobacco, cocaine, and heroin use [14•]. Of note, the findings from this study were not limited to bisexual people. However, studies do consistently show an association between internalized binegativity and substance use [31][32][33]. Expectations of rejection also impact bisexual people adversely, including increasing the risk of substance use [42][43][44][45]. Both in-person and electronic bullying are associated with substance use among bisexual youth [46].
Bisexual people are less likely to disclose and more likely to conceal their sexual orientation compared to gay and lesbian people [37, 47,48], and concealment is generally associated with adverse health outcomes [31,49,50]. However, there is also evidence that disclosing one's sexual orientation is associated with greater substance use for bisexual people [50].  found that being more open about one's sexual orientation was associated with greater substance abuse for bisexual women, but not lesbian or queer women; the association between outness and substance use for bisexual women was due in part to experiences of discrimination [51]. Furthermore, Feinstein et al. (2019) found that being more open about one's sexual orientation was associated with increases in marijuana and illicit drug use for bisexual, but not gay or lesbian, men and women (Note: study included 5 transgender individuals) [25]. In addition, in line with the minority stress model, ongoing experiences of prejudice and discrimination from both heterosexual and gay/lesbian communities heightens vulnerability to substance use [21]. Overall, there is growing evidence that these aforementioned proximal risk factors serve as mechanisms linking distal stressors to substance use [31,49,50].

Intersectionality
Finally, intersectionality-rooted in Black feminist scholarship [52][53][54][55][56][57][58]-is key to understanding bisexual people's substance use. A growing body of evidence suggests that substance use disparities are not just explained by minority stress, but they are related to socio-structural inequities that impact people on the individual-level in their daily lives [52,53]. For bisexual people with additional marginalized identities (e.g., bisexual people of color, bisexual transgender people), intersecting systems of oppression influence health outcomes in unique ways. Substance use disparities are also linked to bisexual people's disproportionate exposure to trauma in childhood and adulthood and structural factors (e.g., disproportionate rates of poverty) [52][53][54][55]. Understanding these interlocking inequalities and realities for bisexual people is key to also understanding their substance use.
That is, the intersections of sexual orientation, gender identity, race, ethnicity, and other social statuses result in exposure to unique socio-structural inequities, highlighting the need to attend to the diversity of the experiences of bisexual individuals. While bisexual people are generally underrepresented in research on sexual minority health, bisexual people of color are especially underrepresented. For example, Ghabrial and Ross (2018) reviewed 324 quantitative studies on depression, anxiety, smoking, substance use, and suicidality that included bisexual participants, and found that only 40% reported the number of bisexual people of color in the sample and only 7% reported outcomes for bisexual people of color separately from outcomes for white participants and other sexual minority participants [56]. The lack of empirical attention to bisexual people of color is particularly concerning given that this population is more likely to identify as bisexual than white individuals [57] and that increases in bisexual identification over time are especially large for people of color [1]. Furthermore, some of the structural disparities affecting bisexual people are especially large for bisexual people of color, including a systematic lack of access to economic and material resources [57].
Despite the importance of considering intersectionality, few studies have examined substance use among bisexual people at the intersections of other minoritized identities (e.g., race, ethnicity) [52,54,55,58]. In an exception, Dyar et al. (2020) found that Black and Latinx bi+ people assigned female at birth reported less substance use and problems compared to white bi+ people assigned female at birth (Note: study included 32 transgender participants, 71 genderqueer/nonbinary individuals) [36]. Furthermore, they found that enacted monosexism was associated with substance use and problems for white, but not Latinx, bi+ people assigned female at birth. Evidence also suggests that enacted monosexism is more strongly associated with substance use/problems for bi+ gender minorities compared to bi+ cisgender women [36], noting that a substantial number of bisexual people are also gender minorities [57].
Similarly, Feinstein, Turner, et al. (2019) found that bisexual youth of color generally reported less substance use than white bisexual youth, although findings differed by sex. For example, Black bisexual girls reported less lifetime cigarette use, past-month binge drinking, and lifetime illicit drug use than white bisexual girls, but this pattern was not observed among bisexual boys [46]. In contrast to this general pattern, they also found that Black bisexual youth (regardless of sex) were more likely to report lifetime marijuana use than white bisexual youth. Some of these findings (e.g., that Black bisexual girls were less likely to report past-month binge drinking and lifetime illicit drug use than white bisexual girls) became non-significant after accounting for past-year bullying exposure [46], which highlights the need to account for important risk factors such as bullying in order to understand substance use disparities. Another recent study by Schuler et al. (2022) found that bi+ women were at an elevated risk for heavy episodic drinking relative to heterosexual women in their racial/ethnic group and the magnitude of this disparity was greater for both Black and Hispanic bi+ women relative to white bi+ women [59]. A few other studies have examined differences in substance use by race/ethnicity in bisexual populations, yet it is more common for researchers to control for race/ethnicity rather than examine its intersections with sexual orientation and gender identity.
In addition, sexual minority people of color experience stressors that white sexual minority people do not experience, including racial and ethnic discrimination as well as intersectional discrimination (e.g., racism within the LGBTQ + community, and heterosexism within one's racial or ethnic community). Qualitative studies have revealed that bisexual people of color experience unique stressors at the intersection of their sexual orientation and race/ethnicity, including invisibility, isolation, fear of being excluded and experiencing violence from their racial/ethnic community, experiences of family rejection, invalidation, disregard, and erasure of their bisexual identity [60][61][62]. Some researchers have suggested that sexual minority people of color experience additional stress due to having multiple marginalized identities, which can overburden coping resources and lead to negative health outcomes. Few studies, however, have examined these unique stressors among bisexual people of color. Bostwick et al. (2021) found that more frequent experiences of intersectional microaggressions were associated with more marijuana use and binge drinking among bisexual women of color [63]. Overall, these findings show the importance of disaggregating data to examine how intersecting social positions lead to unique experiences of inequality, and they highlight the need for research on the unique experiences of bisexual people with intersectional identities in relation to their substance use behavior.

New Directions
Where do we go from here? The above research documents undeniable links between bisexuality and substance use. To be clear, bisexuality itself is not a risk factor for substance use. Rather, bisexual people experience unique risk factors (e.g., binegativity; anti-bisexual discrimination) that put them at greater risk for substance use and problems relative to their heterosexual and gay/lesbian peers. It is worth noting, bisexual people of color report less substance use than white bisexual people (a few exceptions withstanding [59,64,65]) although they also experience unique stressors that contribute to their substance use.
Moving forward, we map out a few key areas in need of further exploration. First, there is a need to better understand the ways in which different dimensions of bisexuality (attraction, behavior, and/or identity) are related to substance use. For instance, McCabe et al. (2005) found that men who were either attracted to or had sex with both men and women were more likely to report substance use than those who were attracted to or had sex with only women, regardless of sexual identity. Other studies have echoed this finding whereby mostly heterosexual individuals who engage in bisexual behavior are also at higher risk for substance use relative to mostly heterosexual people who do not engage in bisexual behavior. It is worth noting, however, that bisexual behavior is not inconsistent with a mostly heterosexual identity. Together, these findings suggest that regardless of how a person identified, if they reported bisexual attractions or behavior they were more likely to report substance use.
One way to address high rates of bisexual people's substance use would be to combat stigma and discrimination across levels of the ecological model, pairing structural interventions with those focused on individual resilience and well-being. Future interventions would also benefit from being developed from an intersectionality framework. For instance, more supportive social contexts can be created by addressing both distal and proximal risk factors as well as the interlocking effects of structural inequities. Several existing interventions designed to tackle more distal determinants (e.g., discrimination) have been shown to reduce substance use. Yet it is unclear whether effects are different for bisexual people and if/how these interventions would need to be tailored to better address the needs of bisexual people (e.g. by working with bisexual communities to do more qualitative, translational, and community-based evaluations). Such interventions include: anti-bullying school district policies [66], the development of Gender and Sexuality Alliances (GSAs) [67], ratification of state-level same-sex marriage laws [68], and policies that prohibit SGM discrimination [69,70].
In terms of more proximal risk factors, interventions that have been successful at reducing substance use among sexual minorities include (1) Affirmative Supportive Safe and Empowering Talk (ASSET), which is a school-based group counseling intervention to bolster resiliency [71]; (2) Safe Space training programs for K-12 schools [72]; (3) Lead with Love, a film-based intervention to help parents of LGBTQ + youth improve their behavior towards their children [73]; (4) Effective Skills to Empower Effective Men (ESTEEM) for bisexual and gay men [74]; and (5) Empowering Queer Identities in Psychotherapy (EQuIP) for gender diverse sexual minority women [75]. Of note, effects were marginally significant for alcohol use problems using the EQuIP intervention. To date, ESTEEM is the intervention with the most evidence, but it is unknown whether findings are the same for gay/lesbian vs. bisexual people. Expressive writing interventions have also been conducted with gay and bisexual male college students [76] and lesbian women [76], and could be translated to support bisexual people by asking them to write about the most difficult aspects of being bisexual, following the approach used for gay and lesbian people [76,77].
Successful interventions focused more specifically on internalized binegativity also could support bisexual people in reducing substance use. These include an online intervention for reducing internalized binegativity [78]. The online intervention included exercises designed to help bisexual people challenge learned stereotypes about bisexuality, identify external sources of binegative beliefs, acknowledge the positive aspects of being bisexual, and express support to another bisexual person. Bisexual people reported decreases in internalized and anticipated binegativity as well as increases in identity affirmation (i.e., pride) from pre-to post-intervention, but effects were small. Additional research is needed to examine the durability of these effects over time, and whether reductions in internalized binegativity have downstream effects on substance use.

Conclusions
In conclusion, the field has made great strides in documenting disparities in substance use among bisexual people. Researchers have identified some central predictors of substance use risk including minority stress and intersectional forms of discrimination. Yet, our understanding of exactly how and why bisexual people remain at such high risk could still be deepened. In particular, future work should continue to explore the context of substance use (e.g., alone vs. with others, with LGBTQ + vs. non-LGBTQ + people, in general vs. before sex) and its origin in the lifecourse. As researchers, we should also focus on how to measure bisexual-specific forms of discrimination at different levels including structural stigma against bisexual people and societal invisibility and erasure of bisexuality. Given that little work has been done on this, additional focus will be needed to determine how to best assess and address various forms of bi-specific discrimination. At the structural level, we have developed relatively good measures of structural stigma against gay/lesbian people. For example, research has used community-level homophobic attitudes and implicit biases (e.g., Miller et al., 2011), voter referendum (e.g., Flores, Hatzenbuehler, & Gates, 2018), gay/lesbian political representation (e.g., Homan, 2019), and social policies that target gay/lesbian groups or that restrict their rights (e.g., Raifman et al., 2018). Structural measures of biphobia, however, are less developed in terms of their specific effects on bisexual people. In trying to support bisexual people, we must remain wary of focusing only on why this group is vulnerable and at high risk, emphasizing instead their forms of resilience and resistance. Finally, let us not forget that bi+ people are one of the fastest-growing demographic groups. As more people identify as bisexual and bi+ , we must as a society find ways to support their growth, health, and wellbeing.
Funding Jessie Ford's time was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism (K01AA028532-01A1). Brian Feinstein's time was supported by a grant from the National Institute on Drug Abuse (K08DA045575). The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agency.

Conflict of Interest
The authors declare no competing interests.

Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
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