Mick Finnegan knows what it is like to have nothing, to sleep rough on the streets and to feel that no one in the world cares.
Yet remarkably the 37-year-old, whose suicide attempt made national newspaper headlines, has defied the odds to completely turn his life around to study for a career in caring at Trinity College Dublin.
His story is both heartbreaking and inspirational and Mick tells it with one motive - to help people who are in a dark place realise that life can get better.
A Dublin native now living in Belfast, he has worked in homeless shelters in the city and more recently in peer support in the psychiatric intensive care unit at Bluestone in Craigavon.
Now planning a career in social work or mental health, he has started a one-year access course at Trinity College with the hope of going on to study for a degree.
A keen rugby coach who works with young people in Portadown Rugby Club, he also has set up his own charity to support players' mental health - State of Mind Rugby Union.
Given how focused and positive Mick is now, it's hard to fathom that up until he moved to Northern Ireland two years ago, his life had been blighted by tragedy.
He was abused as a child at a youth group and, reflecting on his life today, he now realises that he was struggling with mental health issues throughout his teens and 20s.
It was only five years ago that he was finally diagnosed with bipolar disorder, complex PTSD (post-traumatic stress disorder) and EUPD (emotionally unstable personality disorder).
Finally getting the correct diagnosis and receiving proper treatment for his illness has proved crucial in allowing him to turn his life around. Mick recalls how his problems escalated in his mid-teens when he found himself homeless and sleeping rough on the streets of Dublin.
"I was struggling really badly and had been abused but nobody believed me," he says.
"I had behavioural management issues and, looking back, I was struggling with mental health although I didn't know it at the time. I was about 16 when I was kicked out of the house and found myself living on the streets.
"I was in and out of homeless services for years. In fact, just last year at Craigavon Hospital I was diagnosed with a lung condition which the consultant believes could have been caused by sleeping out in the cold.
"I slept out in all weathers. I remember waking up and being so cold that I felt I was stuck to the cardboard I was lying on."
Mick was helped into work in a homeless shelter in Dublin by a support group, and when he was 20 he spotted an advertisement for a similar job in London.
He applied, was successful and moved to the city where for more than 10 years he battled mental health issues, again going through periods of sleeping rough. He also made several suicide attempts, one of which created national media attention.
"In 2009 I had a manic episode but I didn't know that was what was happening to me. I ended up on a bridge in London in a four-hour standoff with the police. They eventually got Major Howard Russell of the Salvation Army to talk to me. He had worked in Dublin and been kind to me when I was first on the streets in my teens.
"He's been the only consistent person in my life and has always been there for me. He talked me down.
"He told me that he loved me and that really affected me as I had gone through my life not expecting love and dealing with a lot of rejection and loneliness. He reached out and showed kindness and compassion."
Mick was sectioned under the Mental Health Act but found himself the subject of intense media interest when British Transport Police decided to charge him with trespass, public nuisance and obstructing a railway line.
He faced the prospect of having to pay £24,000 to Docklands Light Railway in compensation for lost revenue for the four hours the line was shut while police negotiators talked him down from the bridge.
Prosecutors eventually dropped the case as it was deemed to be not in the public interest.
Mick recalls: "I ended up in a psychiatric intensive care unit and I stayed there for a while. When I was discharged I was arrested and put in a cell and held there until I appeared in court.
"Eventually after months of going back and forward to court and being all over the news, it was decided that it wasn't in the public interest to pursue the case.
"There had been a lot of condemnation of the railway company for pursuing the case and the papers challenged the stigma of mental health. It was the first case of its kind.
"I struggled a lot during that time and was suicidal on a number of occasions. I went back to hiding away from people.
"I slept in Hyde Park and there was a comfort in that, although I know that sounds really strange, but I felt safe and away from everything."
The turning point came when he again decided to take his own life. While making the attempt, however, he realised he actually didn't want to die and that he needed help. It was the start of a long journey back to health and normality.
"That was the catalyst for change for me as I realised I had a lot of trauma that I needed to address or it would haunt me for the rest of my life. That's when I was diagnosed and got support from local mental health teams.
"They put me on a lot of medication, and while initially I was quite reluctant to chat about things, I knew I had to do it if I wanted a better life."
Mick started work again and four years ago saw a vacancy for a job helping out in the Welcome Centre for homeless people in Belfast. He got the job and moved to the city, which he has now made his home.
He stayed for a year at the Welcome Centre and then moved to the Depaul Hostel in Garmoyle Street in Belfast. He continued to have his own struggles and made contact with local charity Action Mental Health, which provided support while he made a new life for himself.
Two years ago he secured a job in peer support with the Southern Health Trust, working at the Bluestone mental health unit at Craigavon Area Hospital.
He found himself mentoring people in the same unit he had spent time in while he lived in London.
"It was unusual as I had gone from being a patient and a service user to being a service provider," he says.
"I was really lucky I got in and it was a great experience, which made me want to pursue further education and it has opened up other opportunities for me."
Two years ago he was invited by London's Royal College of Psychiatrists (RCP) to be an adviser with the National Collaborating Centre for Mental Health.
And this month he was also invited to join the Expert Reference Group, a new initiative also run by the RCP to help develop a competency framework for peer support.
His life couldn't be more different today than that of the terrified man who stood on a London bridge 10 years ago wanting to die.
"I do have to ask myself sometimes: 'Is this actually happening?'" he admits.
"I go back and forward to England as part of the national advisory group, working along with psychiatrists, senior nurse managers and senior health care professionals helping to shape mental health policy and improve services.
"I am quite proud that being from inner city Dublin I am able to contribute and help to improve services and training in hospitals in England.
"It's a bit surreal and at times I have to pinch myself."
In what is another surreal move for him, Mick started an access course in Trinity in September with plans to go on and study for a degree either in social work or mental health nursing.
While he has the personal experience of mental health issues, he wants to acquire the knowledge to make a real difference to the lives of others.
His own mental health is something he keeps a close eye on and continues to battle, albeit with great support.
He says: "Working with my colleagues in the Southern Health Trust and the NHS in England I want to acquire a more professional background to be able to underpin my knowledge, skills and practices.
"If you had told me when I was 15 that I would one day be at Trinity College I would have laughed at you. I'm in a good place now, although I still get bad days - don't we all? But it's about how I handle them now. I have a brilliant GP in Belfast, Dr Mark McCrory, who is there if I need anything and he ensures I am looking after my mental health. He would ring me if I hadn't been in for a while.
"He is just fabulous and one of those people who is passionate about his job and I feel really lucky to have him."
Mick has made a huge impact on others struggling with mental health problems, particularly through his charity State of Mind Rugby Union.
The charity is now nationwide and has a number of professional rugby stars as ambassadors.
Mick travels to schools and youth groups across Northern Ireland spreading the message that it is good for our mental health to be able to talk.
He trained as a rugby coach with Saracens rugby team in London after appearing on a TV show. He explains: "I came to the game quite late. After my last suicide attempt I got a place in The School Of Hard Knocks, which was a TV programme on Sky where people who had never played sport before teamed up with professional sports stars.
"That led to all sorts of opportunities. Since coming to Northern Ireland I have coached the youth teams in Portadown Rugby Club a few times, which I have really enjoyed."
In sharing his story, Mick hopes to reach out to anyone who is in despair.
His message is a simple one. He says: "I want people to know there is no shame in reaching out for help and that it is okay not to be okay.
"It's about knowing how to recognise the feelings and then about how we manage it.
"We tend to self-medicate or hide ourselves away when what we need to do is access the support that is there for us.
"No matter how dark a place you find yourself in there is always a way out of it and it really is good to talk about our feelings."