He has been 'clean' for six years now, but still remembers clearly his past addiction.

Mr Andrew Tan used to pop up to 20 sleeping pills a day. Today, he still faints occasionally and suffers from short-term memory loss.

The 36-year-old IT specialist was introduced to sedatives such as Erimin-5 and Dormicum while he was doing his national service. He said he took them so that he could get high while clubbing.

He explained that so long as he kept moving about, he was relaxed yet active. 'Then you get sleepy as it wears off,' he said.

In 1995, he was caught for taking Erimin-5, a banned substance, and went through prison and rehabilitation for about five years.

When he was released, he thought he could control himself, but fell back into the habit even more heavily.

He would ask his boss to pay him daily instead of monthly so he could spend up to $100 a day on the pills.

'On the black market, as long as you have money, you can get as many pills as you want. I could take up to 20 a day, taking a few every four or five hours,' he said.

'Without them, I felt uneasy, with no appetite and my nose would run. I just kept taking them until I didn't know what I was doing.'

He has seen four or five friends commit suicide because of their addiction to sleeping pills, he said.

Once, his boss had to pay for $13,000 worth of computer equipment because he damaged it while in a drug-induced haze.

Finally, in 2002, he realised his life would be meaningless unless he quit the pills for good. He decided to go cold turkey but fainted twice because his body shut down, and he had to be hospitalised.

'In hospital I was aching and suffering but I knew I had to do it. I told them not to give me any medication and to tie me down to the bed so that I could not run away.'

After three weeks of this, he went to the Christian Care Services' Singapore Care Centre halfway house for full-time rehabilitation and has not looked back since.

With the help of counsellors and his Christian faith, he remains clean and volunteers daily with the halfway house, preparing pamphlets and magazines using his IT skills. In return, he gets daily meals.

Said the soft-spoken father of an 11-year-old girl: 'Now, I have the opportunity to encourage other addicts. My family too, is happy with my progress.'