High Ventral Striatal Reward Reactivity Protects Against Depressive Symptoms in Sexual Minority Adolescents

• In Event: 3-141 - Neural Reward Reactivity and Adolescent Psychopathology and Substance Use: fMRI and ERP Studies

Integrative Statement

Introduction: Sexual minority adolescents (SMA) experience higher rates of depression compared with their heterosexual counterparts (Marshal et al., 2013). Adolescence is a critical developmental period in which vulnerability for and rates of depression increase. This may be due to factors altering the experience of reward. Blunted reward sensitivity and disrupted neural reward processing contribute to the development of depression. Previous work has demonstrated neural differences among SMA when processing social reward that is related to depressive symptoms (Eckstrand et al. 2018), yet the neural mechanisms remain unclear. The minority stress model posits that sexual orientation stress (e.g. discrimination) contributes to depressive symptoms among SMA (Meyer, 2003). Stress alters reward processing by blunting ventral striatal (VS) reactivity to reward (Corral-Frias et al., 2015). The purpose of this study is to examine VS reward reactivity and its relationship to sexual orientation stress and depressive symptoms.

Hypotheses: In a community sample, sexual orientation stress would be associated with blunted VS reward activity and depressive symptoms.

Study Population: SMA and heterosexual adolescents recruited from a large urban city.

Methods: Fifty-five adolescents ages 14 to 22 (20 heterosexual, 35 SMA; 27M/28F) participated in the study. Participants were asked to which gender(s) they were attracted and assigned as SMA if same-sex attraction was disclosed. Participants completed the Center for Epidemiologic Studies Depression Scale (CES-D) and disclosed recent social stress related to race, sexual orientation, gender, and weight. All participants underwent functional magnetic resonance imaging (fMRI) with a monetary reward task (Forbes et al., 2009); VS reward processing was defined as the difference of VS activation in anticipation of a win compared to anticipation of a loss. Data was analyzed using standard procedures with SPM12. Multivariate linear analyses implemented in SPSS examined the association between sexual orientation stress and VS reward reactivity. Mediation-moderation models were implemented using PROCESS to examine whether high VS reward reactivity was protective for the association between sexual orientation stress and depression. All models were corrected for age, gender, and race.

Results: In a multivariate linear regression model, depressive symptoms were predicted by sexual orientation (t[9,45]=2.83, p<0.01) and sexual orientation stress (t[9,45]=2.40, p=0.02), but not by other social stressors, race, gender, or age. Sexual orientation stress mediated the relationship between sexual orientation and depressive symptoms (LLCI=0.66, ULCI=10.42). After correcting for other social stressors, sexual orientation stress was associated with lower left VS reward reactivity at trend levels (F[1,40]=3.00, p=0.07). However, left VS reward reactivity moderated the association between sexual orientation stress and depressive symptoms (p=0.03), where only individuals with low VS reward reactivity experienced greater depressive symptoms with greater sexual orientation stress.

Discussion: Sexual orientation stress was associated with greater depressive symptoms, even after correcting for other social stressors. LVS moderated the association between sexual orientation stress and depressive symptoms. This suggests VS reward reactivity may be a characteristic influencing the development of depressive symptoms in the context of sexual orientation stress. This study is the first to demonstrate a plausible mechanism for the development of depressive symptoms among SMA.
 

Authors

• Kristen Eckstrand, 1University of Pittsburgh
  Presenting Author

• Luis Flores, University of Pittsburgh
  Non-Presenting Author

• Melissa Nance, University of Pittsburgh
  Non-Presenting Author

• Brian Thoma, University of Pittsburgh
  Non-Presenting Author

• Michael P Marshal, University of Pittsburgh
  Non-Presenting Author

• Erika Forbes, University of Pittsburgh
  Non-Presenting Author