Bisexual people are more likely to have higher levels of anxiety than gay men and women, as well as heterosexual people.
Research carried out by the Office of National Statistics found people who identify as lesbian, gay and bisexual tend to rate their quality of life as lower than the UK average.
People who identified as bisexual had the biggest well-being gap, reporting significantly higher levels of anxiety than any other group, as well as reporting lower levels of life satisfaction and happiness.
Some 30% of people who identified as bisexual reported high levels of anxiety, compared to two in 10 (19%) heterosexual or straight people.
People who identified as heterosexual or straight reported higher levels of life satisfaction and happiness than their LGB counterparts.
Those who identify as "other" or "do not know or refuse" also said they had lower life satisfaction and happiness than the UK average.
The 2015 Annual Population Survey suggests there are 920,000 people in the UK who identify as gay, lesbian, or bisexual, making up 1.7% of the population. London has the highest proportion of LGB-identifying population.
More men say they identify as bisexual or gay than women, but more women than men identify as bisexual, according to ONS data.
Another 2.2 million people say they don't know, or refused to answer, while an estimated 206,000 identified as "other".