I did not know what I was doing to my mum and dad, let alone myself. (That's) my main regret. It's about time I gave my folks something back (that) they deserve. A son they can be proud of".
These are the words of troubled Matthew Lyle, written during his desperate battle to overcome his drug and alcohol addictions.
They were lying by his side when he died of a drugs overdose at the age of 28.
"What happened to Matthew is a very tragic example of how experimentation on so-called recreational drugs leads to disaster and tragedy. Once the drugs get a grip they just pull you down and down to a life of misery," said Matthew's father, David Lyle.
"Cocaine is an example of a fashion drug whose users dice with death. People think cocaine is a designer toy they can play with, well they can't. Look what experimentation did to Matthew."
Matthew was 15 when he began experimenting with drugs. He started out taking drugs like ecstasy, magic mushrooms, LSD and cocaine, before ending up addicted to heroin and an alcoholic.
He fought a long struggle to beat his addictions and was recovering from his alcohol and heroin dependency when a moment of weakness in September 2005 claimed his life.
Matthew was discovered by his parents in his bedroom, curled up like a ball. A used syringe lay beside his body.
A post-mortem examination showed that Matthew had been killed by tiny doses of not only morphine and dihydrocodeine, but diazepam as well.
"He gambled his life on drugs and lost. That day he had been talking about his hopes for the future but he took a risk on a small amount of drugs and his payback was death," said David, who is managing director of Belfast advertising agency Lyle Bailie International.
While Matthew struggled to stay off drugs and alcohol local dealers would hound him, urging him to buy a fix.
David said that on the day Matthew died, minutes after he had talked with his father about his hopes and plans for the future, a drug dealer stopped him as he cycled to his home in Co Down.
"They never left him alone. The dealers are often themselves addicts, using dealing to pay for drugs. They become very exploitative, targeting young people, trying to move them up the chain from recreational drugs to harder things.
"Matthew couldn't walk down the streets of Bangor without meeting a dealer or couldn't get a train into Botanic Avenue, where he said he was surrounded by dealers."
Nothing will ever ease the heartache of losing Matthew, but it was a tiny consolation for his family when a man who offered to supply him with one of the illegal drugs involved in his death was convicted of drugs offences in October.
"I tried to reach Matthew over many years and failed. My failure to get through to him is the greatest failure of my life and it is a burden that I will carry with me always," said David.
He warned: "Getting involved in drugs is a dreadful downward spiral into deceit, deception, lies, theft. It is a nightmare life.
"Matthew's case is a classic example of a nice kid who got caught up in drugs and his life was then ruined by drugs and alcohol.
"This is a tragic warning and I hope people see his story and think that could be me. Playing with drugs will kill them."
Or in Matthew's own words, written on the sheet of paper that lay beside his lifeless body: "Drugs, abuse of substances, rob you mentally, physically, emotionally and spiritually, rob you of being human."
Matthew's story can be read at www.matthewlyle.info