Sexual identity inequalities in the co-occurrence between poor mental health and health risk behaviours – A national cohort study

Background Mental health challenges (MHC) like depression and anxiety, and health and risk behaviours (HRBs) are more common among sexual minority adolescents (SMA) than in heterosexual peers. Limited studies have examined the co-occurrence between poor mental health and HRBs, whether risk for co-occurrence differs by sexual identity, and associated risks for self-harm and attempted suicide in adolescents in the UK. Methods This study included 10,233 adolescents aged 17 (51% female and 11% sexual minority) from the UK-wide Millennium Cohort Study. Sexual identity, MHC, HRBs, self-harm and attempted suicide were self-reported by adolescents. MHC were assessed using the strengths and difficulties questionnaire [SDQ] emotional symptoms subscale for depression/anxiety. Seven common HRBs (like regular smoking, drug use and risky sexual behaviour) were assessed. Associations between sexual identity and risk for co-occurrence between MHC and HRBs were assessed using multinomial logistic regression. Predicted probabilities for self-harm or attempted suicide based on sexual identity and MH-HRB co-occurrence status were estimated using logistic regression models with appropriate interactions terms (between sexual identity and MH-HRB co-occurrence status variables). Results MHC prevalence was higher in gay/lesbian (48%) and bisexual (49%) adolescents compared to heterosexual peers (19%). Prevalence of self-harm (bisexual: 64%, gay/lesbian:53%, heterosexual:19%) and attempted suicide (bisexual: 24%, gay/lesbian:17%, heterosexual:6%) were higher in sexual minority adolescents compared to heterosexual peers. Gay/lesbian and bisexual adolescents consistently reported higher risk for MH-HRB co-occurrence compared to heterosexual peers (for example, for gay/lesbian individuals: RRR3.16 [95% CI 2.14–4.68] for MH-1HRB, RRR3.54[95% CI 2.06–6.08] for MH-≥3HRB, for bisexual adolescents, RRR2.44 [95% CI 1.85–3.20] for MH-1HRB, RRR4.11[95% CI 2.99–5.66] for MH-≥3HRB). MH-HRB co-occurrence and sexual minority identity were independently associated with risk for self-harm or attempted suicide. Gay/lesbian and bisexual adolescents experienced higher probabilities of reporting self-harm than heterosexual peers with the same level of MH-HRB co-occurrence. For example, 37.2% of heterosexual adolescents with MH-1HRB reported self-harm. Corresponding numbers were more than twice as high in bisexual (75.7%) and gay/lesbian (77.9%) individuals. Similarly, 58.3% of heterosexual adolescents with MH-≥3HRBs reported self-harm, which increased to 84.6% in bisexual and 83.8% in gay/lesbian peers. Conclusions SMA are more likely to experience MH-HRB co-occurrence, which is also associated with substantially higher risks for self-harm and attempted compared to heterosexual peers. Our findings highlight the need for better public health policies to address poor mental health and associated comorbidities to reduce inequalities in adolescence.