BY the time William Allan arrived at Castle Craig in 2006, his addiction to alcohol was so bad he admits he used to cry himself to sleep wishing to die.

Then 41 and living in Airdrie, the problem had spiralled out of control over 15 years as his business collapsed, his marriage unravelled and he lost his teenage daughter to cancer.

"When I came here, I was dying," says Mr Allan.

"I had three blood clots in my brain. I came here directly from the neurological sciences department in the Southern General Hospital in Glasgow.

"I'd watched my 15-year-old daughter die of cancer. I'd lost my business. I'd been married for 25 years - but all that was gone.

"If you were looking for rock bottom, I couldn't have got any lower.

"I can say with certainty, back in 2006 if I hadn't got into Castle Craig I wouldn't be here today. That's a fact.

"I had been through community addiction teams, I'd been sectioned umpteen times, I'd had outpatient treatment, I'd tried Alcoholics Anonymous. Nothing worked."

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He added: "I really couldn't put a figure on what I was drinking - it was oblivion. When I woke up in the morning, I would drink.

"If I couldn't get alcohol I would take something else. At the end of my addiction it was an existence, it wasn't life. It was like Groundhog Day: drink, sleep, drink, sleep.

"At the end, I can say with 100% honesty I did not want to wake up. If I was conscious enough, I used to cry myself to sleep praying to God that I wouldn't wake up in the morning."

Mr Allan, now 55, was one of 144 people publicly funded to undergo detox and rehabilitation at the facility in 2006.

The former auditor spent nine months in treatment and left determined to turn his life around.

He went back to university and ultimately qualified as an addictions therapist, going on to work with projects in Australia, Hawaii, Vancouver, and San Diego, before returning to Scotland where he has worked with homeless people and domestic abuse survivors.

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Mr Allan is now a specialist addictions therapist at Castle Craig, but despite his own success stresses that no one should enter rehab lightly.

He wants anyone referred by the NHS to be screened first to ensure they are psychologically and emotionally ready to benefit.

"It's not a silver bullet," he says. "It's not just about referring people and saying 'we'll pay for it'.

"If that person doesn't know what they're engaging in, they're going to be like a deer in the headlights.

"The number of people we see here who relapse and then come back and say 'I was only doing it to keep my wife' or 'I was only doing it to keep the court off my back' or 'to keep my job'. It's not enough to hit rock bottom.

"You have be prepared for it and committed to change."