The grieving family of a cannabis user have told how they believe the drug killed him.

John O’Brien, 53, from Swinton, began taking the drug to cope with life-changing brain injuries sustained in a car crash.

But over a ten-year period, the Class B drug took its toll on his body and caused his heart to literally stop working.

A coroner at Bolton Coroner’s Court ruled that the Salford man has died from cannabis cardiotoxicity, a condition which can cause a drop in blood pressure which could prove deadly.

John’s relatives have now issued an urgent warning to others, urging them to be wary of the dangers of smoking the drug.

His twin brother Mark, 54, a builder who also lives in Swinton, said John began taking the drug to cope with the pain of losing his job and relationship in the accident which left him with personality changes and unable to work.

He was travelling in the back of a friend’s car not wearing a seatbelt when he was catapulted forward, hitting his head on the seat in front of him.

Signed off disabled, John developed a £25-a-week cannabis habit. He was found lifeless at home last September by his former partner, who had remained his carer since the accident in 1988.

Because he collapsed partially upright against a sofa, it is thought the cannabis cardiotoxicity starved his brain of blood, leading to his death.

John’s family say people have been stunned that cannabis killed him - and want to speak out to warn others.

Mark said: “Obviously we knew drugs were bad for him but we didn’t think they would kill him.

“He said he’d smoke to forget all the things he’d lost as a result of the car accident.

“We’d always be on at him to give up cannabis and he said he was trying to get off it and was on a cannabis substitute.

“The tragedy was a few weeks before his death he’d joined a gym and really cut down on it.”

Research into the effects of cannabis on the cardiovascular system is still only beginning - but one study found middle-aged men are most likely to be seriously affected.

Evidence was also found that marijuana may trigger pre-existing heart conditions that users were previously unaware of.

Mark said: “When we tell people he died due to cannabis they just don’t believe it.

“If we can stop one more person from smoking cannabis it will be worth it.”