In an interview with the Press Association he said he could identify the moment in the film where it all became too much and a turning point occurred.
He said: "There's a moment in the film where I recognised that this was the last moment we filmed before this wave of depression came over me, and I was idiotic or victim enough, or whatever one wants to call it, of this mad compulsion.
"It seems mad now because I'm on a course of medication for the first time in my life that really seems to be working so it does feel really strange. But at the same time I can recognise that moment.
"And I won't say what it is because I don't want people to look out for it then, but of course it makes my heart sink a little because I think that's so odd because it's such a really wonderfully important part of the film and it's a very pivotal moment.
"And I asked myself if there was a connection between the despair that swept over me whether it was triggered by or at least reinforced by the despair that swept over me at the sheer weight of official homophobia that I was experiencing at that particular point of filming.
"But I'm glad to say at the moment things are much better."
Fry said: "Homophobia stands on a tripod of three preposterous lies - a decent and normal person can see they're lies but somebody who is either themselves poor or feels dispossessed or is looking for someone to blame can follow those lies.
"One that it's a choice, two that we want to recruit and the third even more pernicious one is that we're after children in, not just recruitment, but that we actually want to abuse them - and that is just wickedness.
"There's no more logic in that than saying heterosexuality is wicked because of paedophilia of men against little girls."
Discussing the idea that it may be lifestyle choice, Fry said: "Who would choose to be gay in Iraq or Iran where you could literally be thrown into a pit of fire? It's just absurd.
"Plus I only have to think of my own example: I grew up in a culture which basically told me to be straight because the second lie is recruitment that gay people want to recruit the young into being gay.
"It's a bizarre idea. I've never wanted one extra gay person in the world, there are plenty of us around.
Where to get help
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (noon to midnight)
• The Word
• Depression helpline: 0800 111 757 (24-hour service)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.
- AAP