Gay and bisexual youth have a “tragically high” risk of suicidal behaviour, a new study has claimed.

In a research letter published by the Journal of the American Medical Association (JAMA), it was reported that gay, lesbian, bisexual and questioning high schoolers in the US had a much higher risk of suicide than straight people.

Using data from the 2015 National Youth Risk Behaviour Survey, it was found that 40% of LGBQ youth had seriously considered suicide, 35% had planned suicide, and 25% had attempted suicide.

In comparison to heterosexual teens, 15% had considered suicide, 12% had planned suicide, and 6% had attempted suicide.

“LGBQ teens face staggeringly high suicide risks,” senior study author John Ayers, a researcher at San Diego State University, told Reuters.

“We must recognise LGBQ teen suicide is a national public health crisis and bring extraordinary resources to bear to address the crisis.”

Related: Legalisation of same-sex marriage linked to drop in teen suicide attempts

Of the national survey, which involved almost 16,000 youth, 89% of the participants identified as heterosexual, 2% identified as gay or lesbian, 6% identified as bisexual, and 3.2% said they were questioning or unsure about their sexual identity.

Teens who identified as bisexual were at most risk, according to the study, with 46% saying they had considered suicide in the past year.

“Just fearing how their family or friends may react to their sexual orientation can isolate youth and profoundly harm their mental health,” sociologist Anna Mueller, from the University of Chicago, told Science News.

“Only when we provide them with a climate that does that will we begin to see suicidality drop off in this vulnerable population.”

The 2015 survey didn’t ask about respondents’ gender identity, meaning data for transgender people aren’t available.

Last year, a UK study found that young gay and bisexual men are six times more likely to attempt suicide or self harm compared to men in the same group aged over 45, and are twice as likely to suffer from depression or anxiety.