Brian Pennie has gained a degree in psychology, will next year become a doctor of neuroscience, is currently lecturing in that subject in Dublin's Trinity college and in University College Dublin, and is also a TED talker.
Brian (41), who grew up in a troubled housing estate in Ladyswell, Mulhuddart, north Dublin, blames a traumatic experience when he was a baby for his turn to drugs.
"I came into the world with a condition known as intestinal malrotation. In layman's terms what it actually means is that my intestines were twisted," he reveals in TG4 documentary series Finné.
"I was born in 1978 and it was only in 1985, which is crazy to believe, that the medical practice realised that infants need a general anaesthetic, that infants experience pain like normal human beings."
From experimenting with sniffing petrol as a young teenager, Brian turned to cannabis and then later when he was aged 17 to heroin. He blames his experience as a baby for traumatising him so much he needed an escape.
"I believe as an infant I was treated like an organism, I needed an anaesthetic, I wasn't given an anaesthetic," he claims. "I found that anaesthetic at 17 years of age."
He recalls Ladyswell as being very violent.
"Ladyswell was a very troubled area, it was probably known as the roughest area in Dublin," he says. "There were robbed cars every single night. There was so much violence. I seen people get stabbed, I seen guns down the years. I seen everything growing up in Ladyswell, it was a crazy place."
After getting a buzz from taking ecstasy tablets and cannabis, he then decided to try heroin.
"My first experience of doing heroin was just the most powerful experience in my life," he reflects. "I fell in love for the first time. It was like a soft, warm blanket was wrapped around me.
"The way I describe it is like nirvana on earth. It was making my anxiety just melt away."
Brian began dealing in cocaine to earn more money to feed his habit, even getting his sister to drive him around estates across Dublin as he was incapable of getting behind the wheel of a car himself.
His family was stunned to hear rumours in their area that he was a 'junkie', as he seemed to be living a decent life, working in a graphic design company.
But his habit got worse.
He lost his job because of his habit and the final straw for his family was when cars belonging to Brian and his mother were torched outside their home by criminals who had it in for him.
Brian ended up in a detox clinic in Co Wexford. After several months there he left and then turned to education.
"I had this desire to learn, you could tell I had switched addiction," he says.
"I had this drive to learn, this intense curiosity to learn about psychology, to learn about spirituality, to learn about why I suffered. Why I didn't suffer any more and how I could share it with other people."