Substance use disorders are more prevalent and more severe among sexual minorities, researchers at the University of Michigan have found.
The study, published in the online journal LGBT Health, looked at the severity of alcohol, tobacco and drug abuse as reported by members of the LGBT community and those who were unsure of how they identify.
It found that alcohol and tobacco disorders were particularly severe among bisexuals and those who were not sure of their sexual identity.
Those in the 'not sure' group also had a higher proportion of severe drug use disorders, said lead researcher Carol Boyd, a professor of nursing at the University of Michigan.
She said there was 'strong evidence' that substance use disorders disproportionately affected sexual minorities across the board when compared to heterosexuals.
The study was based on data from the National Epidemiological Survey on Alcohol and Related Conditions-III carried out in 2012 and 2013. Out of the 36,309 adults who took part, six per cent identified as a sexual minority.
Compared to heterosexuals, Boyd found that those who were unsure of their sexual identity were five times as likely to have a severe alcohol abuse disorder and around four times as likely to suffer from severe tobacco or drug problems.
This was far higher than those who identified as lesbian or gay, who were more than twice as likely than heterosexuals to have a severe alcohol or tobacco use disorder.
Bisexual individuals were around three times more likely than heterosexuals to suffer from a severe alcohol use disorder, and two-and-a-half times more likely to have a severe tobacco use disorder.
The study also identified a link between sexual activity and substance abuse, with those who said they did not have any sex in the past year being significantly less likely to report struggling with a substance abuse disorder.
'The severity is what leads to health and social consequences such as poor health, impaired driving and loss of work,' Boyd said.
'We already know that disproportionately, gay men and women go to bars and drink more, so that has been known for decades. But these findings tell us something else - it's about severity of their alcohol and other drug use disorders.'