A study comparing mental health and sexuality over time has found the reported association between non-heterosexual identity and anxiety or depression largely disappears when other known risk factors are considered. In particular, lack of social support is strongly associated with mental health problems. This was particularly common, and serious, when sexual identity was changing.

Numerous studies have found people who identify as non-heterosexual are more likely to describe symptoms of depression and anxiety, contributing to horrifying suicide rates. In some cases, this association could be a product of legislative discrimination, but this cannot provide a complete explanation.

Dr Richard Burns of the Australian National University noticed that almost all the studies were cross-sectional, rather than longitudinal, providing only a glimpse of participants' situation at a moment in time, rather than information on developments with time. Many also lumped anyone who didn't describe themselves as heterosexual together, despite some evidence depression and anxiety are more common among those who identify as bisexual than homosexual.

Fortunately, studies that ask people the same questions at multiple points in their lives are becoming more common. Burns made use of the Personality and Total Health Through Life Project, which tracked two groups of Australians, one aged 20-24 and the other 40-44 when the project started. Although the project didn't ask every question Burns might have hoped for, it included enough information to bring to light things other studies have missed. 

In particular, Burns found that, as one might expect, depression and anxiety are much more common among people who report little emotional support from family and friends, and negative interactions with those close to them. Heterosexuals described much more positive support and lower levels of what is called “negative support”, where family and friends undermined or hurt the participant. Burns told IFLScience that the study did not inquire into whether the negative support represented homophobic bullying, but “we might be capturing that.”

Burns said in a statement: “When we adjusted for these other mental health risk factors, we found no major risk associated with sexual orientation itself.”

 Another key finding from Burns' paper in Epidemiology and Psychiatric Sciences is that those people whose sexual identity was stable over time reported little difference in mental health, irrespective of whether that identity was heterosexual, homosexual, or bisexual. The danger arose when people's sense of their own identity changed in any direction during the course of the study.

The combination of these two findings suggests that what is most important for resolving anxiety and depression among LGBTI people is not just having supportive networks, and an absence of bullying, but having these at the times when people are questioning their sexuality.