SINGAPORE - Ice addicts can become so paranoid that they imagine people screaming at them or that someone is out to kill them.
Some see and feel creepy-crawlies on their bodies and scratch till they bleed.
Ice - the street name for the illegal drug methamphetamine - is a stimulant that affects the central nervous system.
The immediate effects of taking it include euphoria, rapid heart rate, irregular heartbeat and increased blood pressure, said Dr Gomathinayagam Kandasami, chief of the Addiction Medicine Department at the Institute of Mental Health (IMH).
As with most drugs, an overdose can be fatal. Abusers of Ice can also die from dehydration or even heart attack.
Besides physical effects, Ice also affects one's mind and sense of reality.
Psychiatrist Brian Yeo said: "The physical risk is always there, but the paranoia doesn't occur all the time."
Likening it to Russian roulette, he said that some drug abusers may experience the paranoia on their first try.
The consultant psychiatrist at Mount Elizabeth Medical Centre has seen many patients brought in by their family members.
He said: "The ones who still listen to their families will come in for treatment."
Dr Yeo, who has carried out drug detox programmes at his centre for more than 10 years, has seen a whole range of cases.
He said: "Paranoia affects each individual differently. The more aggressive ones may pick a fight while the quieter ones take a different approach - running and hiding."
Some experience auditory delusions such as imagining people screaming at them.
The more serious cases are when addicts try to harm their family members or kill themselves.
Said Dr Yeo: "They feel like everyone is against them and that there's nowhere safe to go. And there's nothing for them to lose."
It takes a combination of counselling and medication to combat the paranoia, he added, stressing the importance of medication during the initial stage.
The paranoia usually goes away after a couple of weeks.
Getting patients to quit is harder, especially if they are used to abusing the drug for pleasure. Said Dr Yeo: "Nothing gives them the same kind of kick they're looking for."
What makes Ice so addictive is the intensity of positive effects the drug provides, said Dr Gomathinayagam.
He said: "Usually, these effects don't last long and the users will suffer an immediate crash after the initial euphoria.
"It's these short but profound bursts of highs that make it hard for a drug user to stop abusing it."
The majority of Dr Yeo's patients are young people in their 20s and early 30s.
At IMH, the patients being treated for their addiction to the drug are mostly men.
Those seeking help can call the All Addictions Helpline: 6-RECOVER (6732 6837).
This article was first published in The New Paper.