Matthew Todd is feeling uncharacteristically nervous. "It's a big taboo, we're expecting it to cause quite a stir," admits the editor of Britain's award-winning gay lifestyle magazine, Attitude. Above the obligatory cover shot of a shirtless Adonis-type torso, this month's mag is labelled "the issues issue". Todd has good reason to be wary of how it will be received. The theme is the worryingly high rates of mental health and dependency problems among gay men.

"There is this cliché that we are all having a great time partying, but actually we know, and the research is now showing, there are a hell of a lot of unhappy gay people; far higher rates of depression, anxiety and suicide than among straight men; far higher rates of self-destructive behaviour; substance abuse and sex addiction; and high levels of issues around intimacy and forming relationships."

Evidence shows that gay men are more than twice as likely to attempt suicide. A research project at London's University College hospital found "significantly higher" rates of mental illness among gay men than their straight peers. "It's an incredibly sensitive issue that gay men are very defensive about," said Todd, "because we fought so long to say we're equal, we're happy with who we are. While that's true, we're are also suffering from the trauma of the journey, the isolation, the secrecy and the shame, and the resulting effect on your mental health that is more likely to happen to you if you grow up gay than if you grow up straight.

"It's about low self-esteem and the self-hating gay man. But the time has come to find the strength to face it and realise that, while it's not our fault this has been inflicted on us, we do need to deal with it." For Todd, realising he was gay at the age of 10 sent him "freefalling into shame". "It was the beginning of the worst five years of my life. I feel for me then and for kids now totally let down by society. I should have been able to talk to my teacher, to my parents. I don't think many people really understand the trauma."

The isolation begins in childhood. "They pick up on the fact that the parents are sensing there's something different too, and that's bad. The child is absorbing all this. Another level of shame. It's a painful thing for people to deal with. Not everyone comes out of the closet shouting hurray!"

After several years of therapy, Todd is starting to deal with his own compulsive behaviours. "The gay scene is incredibly sexualised. Kids come out into this sexualised world where there is lots of booze and lots of drugs, there's nothing that's just healthy, gentle and relaxed. It's empowering to have lots of sex, but only if that's what you actually want, if it's you making the choice."

Some luckier gay men found themselves in supportive environments. Author and broadcaster Simon Fanshawe said going to Sussex University saved him and that the taboo of talking about mental health issues had to end: "Growing up with a burden of guilt is many people's story, mine is just the gay man's story. We have to learn to unlearn the self-hating thing. We need more honesty with each other, less insistence on gay solidarity all the time."

But still, as one gay blogger wrote: "The gay community is truly a wounded lot. In essence, young gay men have no role models in the home, no one to guide them through feelings of insecurity. They know deep down that they are different, but as young people tend to do, they don't view 'difference' in a positive, healthy light. They come to believe that they are inherently flawed, unlovable, second-class citizens."

A lack of high-profile role models is often complained about. Many of the most visible gay celebrities are those whose own "issues" have become only too public – Michael Barrymore, George Michael, Lindsay Lohan, Boy George, Alexander McQueen. It may be true, as Julian Clary said, that "the British people have a soft spot for a gay entertainer", but many men do not feel confident in coming out. In May, Treasury minister David Laws had to resign after his efforts to keep his sexuality secret were undone when it was revealed he was paying rent to his partner in breach of parliamentary rules.

Afterwards he said: "I suppose it was pretty stupid because all the people I have spoken to have accepted it [my sexuality] without hesitation."

Rugby player Gareth Thomas, 35, lived a lie for many years before coming out as gay, but only after attempting suicide. This month, he topped an impressive list of talent, the annual Pink List of the 101 most influential gay and lesbian people in Britain. In the words of one of the judges, Clare Balding, they "challenge the accepted view of gay men and women. They are supremely successful, confident and bold, they are very visible, and they happen to be gay. They don't need to march or wave a placard but, in their own way, they have had a huge impact."

Things may be changing, but the damage inflicted by homophobia and growing up "different" has already been done for many gay men. "Homosexuality" was not taken off the list of psychiatric disorders until 1993, making it especially difficult for older gay men to reveal their sexuality to mental health providers, said Dominic Davies, director and founder of Pink Therapy, the UK's largest independent counselling organisation working with gender and sexual minority clients: "If you don't feel you can trust your doctor, you are not going to disclose to them. We have had quite robust research that shows significantly poorer mental health among gay men and lesbians than in the general population and significantly higher rates of drinking, smoking and drug-taking. The result of living as a stigmatised minority is that you self-medicate."

Tim Franks of the gay and lesbian charity Pace said mental health providers in Britain are blind to the problem. "Of the young people coming into our workshops, around one in four has already attempted suicide. They are isolated and in hiding almost, they don't know who the safe people are. The current word for bad in British schools is 'gay', and children internalise this stuff very easily, they think in terms of good and bad. So by the age of 10 kids have understood that bad people are gay – then they discover they are one of them. They enter a dreadful stage of secrecy which can last 20 minutes or 50 years. Even when you make contact with the adult world, it can be a very sexualised one.

"Imagine if we expected a young heterosexual girl to get her first lesson about relationships in a singles bar. All this is traumatic and has an impact on mental health. It's certainly a far bigger issue than something like HIV and a greater health inequality. A key failure is that mainstream health providers are not assessing this huge need. In effect, you have a system that is blind to a particular type of person."

In his ground-breaking book The Velvet Rage: Overcoming the Pain of Growing Up Gay in a Straight Man's World, US psychologist Alan Downs examines the pain that permeates the lives of gay men and the destructive choices they sometimes make. "Yes, we have more sexual partners in a lifetime than other groups of people," he writes. "At the same time, we also have among the highest rates of depression and suicide, not to mention sexually transmitted diseases. As a group, we tend to be more emotionally expressive than other men, yet our relationships are far shorter on average than those of straight men.

"We have more expendable income, more expensive houses, more fashionable cars, clothes, furniture than just about any other cultural group. But are we truly happier?"

Todd hopes Attitude will help gay men to tackle that question: "If there is a gay community, we need to look after people who are having a bad time. For the first time, we have concrete answers. If you have these issues, there's a way to deal with them."