Richard, 56

The film never states directly that it's about sex addiction, but it very clearly is: in Brandon [played by Michael Fassbender], we see pretty much all the typical sex-addict behaviour. It was very painful to watch; if I weren't so far along with my recovery – I've been going to Sex Addicts Anonymous (SAA) for just over five years – I might have had to walk out.

It's Brandon's absolute cut-offness – his inability to have a relationship – that's so grim, and so real. You feel his sense of despair. I've thrown out all my porn magazines, books and DVDs many times over the years, and it doesn't change anything – the shame diminishes, and then you build it all up again.

Sex addiction is an illness of intimacy, and this comes over very clearly in the film. My recovery has brought me freedom: before, like Brandon in his neat, sterile apartment, I was so tightly wrapped, almost obsessive-compulsive. I couldn't abide mess, but the reality was that my life was a mess. I never downloaded porn at work but I endlessly downloaded all sorts of stuff at home. Thank God none of it was illegal, but I know plenty of people [in SAA] who have been prosecuted for doing exactly that.

Steve McQueen likes long takes: he stays on a image for a lot longer than other directors would, so it feels like you're forced to be there. For that reason, the sex scenes are difficult to watch. They don't come across as erotic; they're more mechanistic: we see a series of grimaces on Brandon's face, and the faces of the women he has sex with. These people look as if they're in pain.

Sarah, 38

Watching Shame was a bit like being in a SAA meeting, listening to somebody share the story of how they got here. In other films about addiction, there's usually a sense of falling into the abyss and coming out the other side. This film is interesting because there's absolutely no redemption at all.

I really identified with the fact that Brandon couldn't have sex with the girl he had started building a relationship with. When there is intimacy, a sex addict might find it difficult to get turned on; that's exactly how I was. An addict needs a series of rituals to get them into what we call the "bubble" or "trance"; for me, it was drinking and music. I can't listen to Goldfrapp any more because it takes me straight into that state.

Although the film is very male- centric, it actually does put across quite well the female experience of sexually addictive behaviour. Brandon's sister Sissy (played by Carey Mulligan) is pretty much a classic sex addict: low self-esteem; a tendency to sleep with inappropriate people very quickly then to obsess about them, and call them up at inappropriate times. Her life is unmanageable, full of pain and drama. I related to that. When I was younger, I had a lot of unsafe sex, and several abortions. When you're in that trance state, you just don't care about anything; you might end up spending too much money, abandoning your kids, or not coming home for three days.

Then there are the women Brandon sleeps with: I'm not saying they're all sex addicts, but none of them is displaying sexually healthy behaviour. In SAA we meet a lot of prostitutes and women who have worked in the porn industry. It's not the sexual behaviour in itself that defines a sex addict – nobody has the right to say that certain behaviours are unacceptable – it's how it makes you feel afterwards: the powerlessness, the obsession, the guilt and the shame.

Stephen, 61

The film's title is incredibly accurate. I've struggled with sex addiction for many years; I finally sought help last year, and I now have a huge sense of shame about the things I've done.

I'm gay, but just change the sex of Brandon's partners in the film, and the experiences we have been through are very similar: I used to visit saunas, cruise in public places such as Hampstead Heath [in London], have casual sex that wasn't about relationships and wholeness and real intimacy.

When I came out in the late 70s/early 80s, gay bars really were down little alleyways, with big wooden black-painted doors and little peepholes. We whispered through the door: "Can I come in?" And someone would say: "Are you gay? Yes you can come in." Now, I struggle with chat-lines; the most fragile time for me is just before going to bed. I think it's about loneliness – I'm picking up the phone and trying to meet somebody; to connect with them.

The addiction is incredibly isolating. Deep down, you feel terribly ashamed of what you're doing: your self-esteem hits the ground and you think you're not worthy of being loved at all. That's why the film works so well: it puts across that sense of alienation. The film's extraordinarily bleak, but the addiction really is a very bleak place to be – so for me, that rings true.

I would have liked to have got more of a sense of where Brandon and his sister have come from. Sex addicts don't just happen: the common factor is an early dissociation from intimacy. I grew up in a very fundamentalist Christian family; I had this sense as a very young boy that sex was a bad, naughty thing; that if God had planned it better we wouldn't have to have sex to have babies. The realisation that I was gay made me feel doubly terrible; I reaped the results of that, and somehow separated sex from love.

Monique, 54

Brandon is a high-functioning, garden-variety male sex addict; we see him going through typical sex-addict behaviour – like the long, lingering look he gives a woman on a train and in a bar, which acts like an unconscious secret signal for sex addicts. But we never really see any of the unmanageability of the addiction. And we see nothing at all about recovery, which I think is very dangerous for anyone with the addiction who might see the film.

He's also a lot less funny and charming than most of the male sex addicts I've met; in fact, he's pretty serious and dull. I've been in relationships with male sex addicts; they're not all tongue-tied and awkward – in fact, a lot of them are very slick. And while we see Brandon having some pretty high-voltage sex, most of the women he has sex with are actually quite demure. He never meets his nemesis.

My big concern is that people are going to see Shame and think: "I don't have this addiction." Sex addiction can manifest itself in a variety of ways, at different stages in an addict's life. I, for example, had a 10-year relationship, and then at 43 I went back into massive sexual addiction.

Sex addiction also has dire consequences for society: we're seeing indiscriminate promiscuity; pornography; loss of intimacy. It's not just a personal issue, it's also a political one. I'd have liked to see the film try to tackle that.

Ben, 54

Sex addiction in this country is pretty much where alcoholism was 50 years ago: it's something that you just can't talk about openly. I was out with some colleagues recently when they started joshing about the women in the office, as blokes do. I didn't feel comfortable talking about women in that way – but I couldn't tell them that in the last three years, my life pretty much crashed and burned because of my sex addiction, and I'm only just dragging myself out of it. I lost my marriage, my job, my family, most of my money; and now I'm having to face up to the pain I caused a lot of people.

It was particularly painful for me to see the way that Brandon refuses to help his sister because he's so obsessed with getting his next fix. She's very needy, but the average, healthy, balanced person would see that and say: "I need to dig deep and do something about it." He's too isolated – and I related to that. There was a long period when my daughters didn't speak to me, and I don't feel I was there for them in the way I should have been.

My hope is that Shame will at least get people talking about the addiction. Before I saw it, I was worried that it might feel a bit sensationalised. I don't think it does, though I am a little concerned that addicts will come away thinking that if they're not exactly like Brandon, living in this incessant, day-to-day way, then they don't have a problem. There are as many ways of being a sex addict as there are people: through the 12-step programme, I've been in rooms with everyone from convicted paedophiles to people who just feel shameful about the fact they look lustfully at somebody across the street.

Most names have been changed. For information about Sex Addicts Anonymous, visit saa-recovery.org.uk or telephone 07843 108302. Shame is out Friday