At age 13, Nathyn Costello picked up a pair of dumbbells at his friend's place and started working out. He was a skinny kid, and had recently watched a couple of Jean-Claude Van Damme movies. He saw the man in the skin-tight singlet showing off his ripped abs and bulging biceps, watched him high kick and fly kick the bad guy and ultimately get the girl. Costello decided then and there what he wanted to be—big.

Seven years later Costello had achieved his dream; his body was buff and sculpted and there was barely a molecule of fat on his frame. But taking his shirt off in front of other men at footy training, eating a piece of fruit and even going out to dinner with friends had become the stuff of his nightmares.

'The best way to think about muscle dysmorphia is like reverse anorexia,' says Scott Griffiths, a psychologist from the University of Sydney whose research focuses on muscle dysmorphia and eating disorders in men.

'Guys with muscle dysmorphia are not trying to be skinny: their ideal physique is lean, cut, and very big, so the type of dieting and exercise they do is different to people with anorexia,' says Griffiths. 'But it's just as aggressive, so they too can look you in the eye and tell you that they're small, even though they're huge.'

In his early twenties, toned, trim and muscular, Costello would sit in the gym, watch other guys walk past and think how fit and strong they looked. He'd catch sight of himself in the mirror and get upset.

Outside the gym, as a coach of a high-level football team, Costello wouldn't take his shirt off unless he knew he was under a certain body fat percentage, and socializing with friends became almost impossible. When he was invited out to dinner he would eat his own meal before or after, or avoid social activities altogether.

Griffiths says Costello's story is a familiar one among the men he speaks with during his research.

'Once those thoughts, feelings and behaviors escape the context of the gym and they start to interfere in personal relationships, your ability to hold down a job and to do your job properly, that's when you need to have that honest conversation with yourself,' he says.

Costello says he knew something wasn't right with his behavior but when he saw his body reflected in the mirror he remained unhappy. So even with his strict diet and workout regime, Costello says he was driven to 'improve the outcome'. He turned to steroids.

Rising from the underground

Steroid use is on the rise in the US.

This recent rise in steroid use is something Ben Ly, a personal trainer, says he has noticed over the past few years among young men, especially among 15 to 25-year-olds.

'They're very impatient; they want to put on muscle as fast as they possibly can, they look at muscle magazines and movies, and see these huge, ripped out guys but they don't realize that [a lot of those guys] have something called 'mature muscle', which is five to 15 years’ worth of weight training that has gotten them to that point.'

Ly says he's also noticed that over the past three to four years, steroid use has become less of a taboo subject.

'Illicit steroid use was very underground, no one would mention it. But even in the last year, it's become very open. Just last week I had two young guys [ask about steroids] and approach us directly at the reception counter, it was like they were just asking for a cigarette or a lighter … it's so big and well used now in society that to them, it's not illegal ... and everybody wants to be a part of it.'

This recent rise in steroid use has Costello worried because it reminds him of his own experience with steroids in the past.

'I knew guys who were using 10 to 30 times [the dosage] I was, and that was very common, and I'd be concerned. These guys would put on a lot more muscle, a lot more quickly, but from my observation they'd also be the ones who were more fragile—they'd run out of the drug, lose a bit of weight, and their confidence would drop through the floor.'

That kind of unregulated and sporadic use also has Griffiths concerned. He says the period of time when someone with muscle dysmorphia is coming off a steroid cycle is critical. He sees some of his clients experience big mood swings and emotional instability, including the risk of suicide.

'For a guy whose body image, self esteem and emotional stability rests heavily, if not exclusively, on how he looks and his appearance, he's going to experience a very rapid drop in muscularity ... and to see that happen over just a couple of days can be quite traumatic.'

Griffiths also says the way in which steroid users have recently been associated with violence in the media has not helped in encouraging men to come forward and seek help. While the taboo around steroid use has diminished, Griffiths says there's still a stigma for men who want to seek help.

'I think to a large extent men are discouraged from talking about their vulnerabilities, especially when it comes to mental illness. I think the perception that muscle dysmorphia is a disorder that men can suffer from hasn't quite permeated through the public consciousness yet.'

Costello was never diagnosed with muscle dysmorphia, but now at age 36, believes he had the disorder in his twenties.

'The truth is I think I just wanted acceptance,' Costello says. 'I was very skinny and wanted to feel more confident, I guess. That's where it started ... the world automatically rewards people who look good, but there aren't enough people who want to be vulnerable to talk about how they're feeling.'