Sexual orientation (SO) microaggressions contribute to mental health issues among sexual minorities. Microaffirmations may mitigate these effects, with internalized heterosexism and SO concealment proposed as mediators. A community sample of 307 Thai sexual minorities completed measures assessing SO microaggressions, microaffirmations, internalized heterosexism, SO concealment, and mental health concerns. Serial mediation analysis using Hayes' PROCESS macro model 6 tested indirect effects through proposed mediators. Conditional process analysis using PROCESS model 85 examined the moderating role of microaffirmations. These models tested hypothesized moderated serial mediation relationships among study variables. SO microaggressions had a total effect on mental health concerns, directly and indirectly through increased SO concealment. The internalized heterosexism → SO concealment sequence mediated this relationship. Microaffirmations moderated the direct microaggressions-mental health link, reducing this association at higher levels of microaffirmations. The full model accounted for 31.6% of the variance (R2 = 0.316) in mental health concerns. The Johnson-Neyman technique identified 0.613 as the microaffirmations value above which the effect of SO microaggressions on mental health was no longer significant. Findings elucidate mechanisms linking SO microaggressions to mental health issues and microaffirmations' protective role among Thai sexual minorities. These results could inform efforts to mitigate minority stress impacts.
Keywords: Microaggression; anxiety; depression; internalized heterosexism; microaffirmation; sexual minority; sexual orientation concealment; stress; subtle discrimination.