Lifetime heterosexist victimization and diurnal cortisol predict depression trajectories among sexual and gender minority emerging adults.

Heterosexist victimization constitutes a severe source of social stress with enduring effects on mental health and the adrenocortical functioning of lesbian, gay, bisexual, transgender, and queer (LGTBQ) emerging adults. However, it is unknown what roles lower or higher diurnal cortisol at waking (cortisol intercepts) and less variable fluctuations ("flatter" slopes) play in the links between heterosexist victimization and depressive symptoms. In accordance with diathesis-stress, allostatic load, and biological embedding perspectives, we examined whether cortisol intercepts and slopes moderated or mediated the predictive associations of heterosexist victimization with depressive symptoms over 24-months. Heterosexist victimization was expected to predict depressive symptoms most strongly for LGBTQ emerging adults with flatter cortisol slopes (i.e., moderation), and cortisol intercepts and slopes were expected to indirectly link heterosexist victimization with depressive symptoms (i.e., mediation). Latinx and White LGBTQ emerging adults (N = 97; ages 18-29, M = 23.91 years, SD = 2.63) provided saliva samples and questionnaire responses during a four-day testing protocol at baseline; two additional assessments of depressive symptoms were completed 9- and 24-months later. Cortisol intercepts and slopes moderated associations of heterosexist victimization with both contemporaneous and prospective depressive symptoms. Heterosexist victimization was positively associated with contemporaneous depressive symptoms and decreases in depressive symptoms over two years when LGBTQ emerging adults also had steeper cortisol slopes. Heterosexist discrimination was associated with increases in depressive symptoms prospectively among participants with lower cortisol intercepts. There was no evidence for mediation. Thus, patterns of diurnal adrenocortical functioning may distinguish between LGBTQ emerging adults who are more prone to acute versus prolonged depressive symptoms when they experience heterosexist victimization.