Background: There are few population-based cohort studies of the emergence, development, and persistence of mental health problems in sexual minorities compared to heterosexuals.We compared trajectories of depressive symptoms from 10 to 21 years of age in sexual minority and heterosexual adolescents, and examined self-harm at ages 16 and 21.
Methods:The study included 4828 adolescents from the ALSPAC birth cohort (Bristol, UK) who reported their sexual orientation at age 16. Depressive symptoms were assessed with the short Mood and Feelings Questionnaire (sMFQ) at seven time-points between ages 10 and 21. A self-harm questionnaire was completed at ages 16 and 21. Analyses were linear multilevel models with growth curves (depressive symptoms), logistic multilevel models (self-harm in the past year at ages 16 and 21) and multinomial regression (lifetime self-harm with and without suicidal intent at age 21).
Findings:In sexual minorities, depressive symptoms were higher at age 10 and increased to a larger extent compared to heterosexuals. In heterosexuals, depressive symptoms increased by 0.31 sMFQ points at each time-point (95% CI 0.27 to 0.34) and in sexual minorities by 0.49 sMFQ points (95% CI 0.40 to 0.59). Sexual minority adolescents were more likely to report self-harm in the past year at ages 16 and 21 (adjusted odds ratio 4.23, 95% CI 2.90 to 6.16), with no evidence that this estimate reduced with age (p=0.798). At 21, sexual minorities were 4.53 (95% CI 3.02 to 6.78) times more likely to report previous self-harm with suicidal intent.