7. Project Summary/Abstract Consistent with NIAAA’s expressed goal to understand sex differences in risk of problem alcohol use and target mechanisms that contribute to known disparities within high-risk communities, the current proposal seeks to examine the role of internal sources of minority stress (i.e., stress unique to those from marginalized communities) in potentiating heavy alcohol use, particularly among female and male bisexual/bi+ individuals. Prior work has focused almost exclusively on sources of minority stress among those who already identify as lesbian, gay, or bisexual. The proposed project seeks to examine physiological and psychological mechanisms that account for consumption among adults who report uncertainty about their sexual orientation, or sexual identity uncertainty (SIU). Uncertainty-identity theory suggests that when someone feels uncertain about a core aspect of their identity, they are motivated to reduce resulting psychological distress, which can account for increased alcohol consumption. No study, to date, has used an experimental design to examine physiological stress responses to ethanol consumption following exposure to internal sources of minority stress. The proposed work will test for differences in consumption and alleviation of distress based, in part, on participants’ physiological stress responses and the pharmacological effects of ethanol. This application proposes to recruit 200 cisgender participants with varying levels of SIU and uses a 3 x 2 x 5 mixed-factorial design. Participants will be randomly assigned to give one of three speeches, as part of an adapted Trier Social Stressor Test (TSST): (a) Relevant Proximal Stressor-TSST: development of their sexuality, including any feelings of uncertainty; (b) Irrelevant Proximal Stressor-TSST: development of their gender identity, including any feelings of uncertainty; or (c) Control-TSST: a recent book, movie, or TV show. Participants will then engage in a 35- minute ad libitum taste-test (ethanol, placebo). Project design includes: (a) a baseline survey and (b) experimental lab session that measures (i) alcohol consumption and 5 assessments of: (ii) breath alcohol concentration, (iii) salivary stress hormones, (iv) heart rate, (v) blood pressure, (vi) psychological distress, and (vii) perceived intoxication. Participants’ SIU and biological sex will alter the effect of condition on consumption. Indirect effects are expected, such that exposure to relevant internal sources of minority stress is expected to increase stress responses, which will account for drinking amount among those with higher SIU. We will also determine the extent to which physiological stress-dampening effects and perceived intoxication account for reductions in distress following drinking, depending on participant sex, whether beverages contain ethanol (or not), and positive beliefs about alcohol’s effects. Results will inform interventions that target physiological and psychological processes, especially those reinforcing use following exposure to internalized minority stressors.

8. Project Narrative The proposed study uses an experimental design to establish causal support for the role of internalized stress, pertaining to uncertainty with regard to one’s sexual orientation, in contributing to heavy drinking behavior. Following exposure to internalized sexual stigma, physiological and psychological stress responses are expected to increase alcohol consumption in adults who are uncertain about their sexual orientation, especially among females, and following consumption, the physiological effects of ethanol and beliefs about the effects of alcohol are expected to alter relations between exposure to sexual stigma and the alleviation of psychological distress. Showing that physiological stress responses, whether driven by the pharmacological effects of ethanol or expectancies regarding its effects, can account for known alcohol-use disparities, particularly in bisexual/bi+ communities, would contribute a great deal to knowledge on the biology of addiction and inform subsequent interventions that seek to regulate stress reactivity.