Grinspoon lead singer Phil Jamieson became withdrawn and paranoid, stealing money from his band to feed his daily addiction. Two-time world surfing champion Tom Carroll recently described how ice made him "completely manic", saying: "It was killing me from the inside out." 

"No one is immune," says drugs expert Rebecca McKetin. "We like to think problems happen to other people but it could happen to us or people like us."

Ice is a highly addictive, crystalline form of methamphetamine, which can be snorted or swallowed, smoked or injected. The high purity and increased availability of the stimulant in Australia over the past decade has attracted a growing range of users. 

"The bulk of people are using it recreationally, they are not 'down-and-out' types, but there is a trickle effect of some people having problems," says Dr McKetin, of the Australian National University. "The drug makes it very difficult for them to control their emotional impulses. They may become more impulsive, paranoid, overly suspicious.

"They are much more likely to act out violently. It adds fuel to the fire. People using the drug heavily often show an irrational type of behaviour that is inexplicable to the person looking on." 

Studies show that aggression, violent behaviour and violent crime are relatively common among chronic methamphetamine users. "They take ice to make them feel good ... but it seems to impact on people's capacity to regulate their emotions," Dr McKetin says. "It can get someone fairly volatile."

Just over 2 per cent of Australians use methamphetamines, compared with 10.2 per cent using cannabis, according to the National Drugs Strategy Household Survey. But ice has proved popular in recent years, particularly compared with ecstasy and heroin.

While the number of people taking methamphetamines remains steady, the percentage of users preferring ice over drugs such as speed has more than doubled since 2010. One in four ice users now take it daily or weekly, up 12 per cent over that time.  

NSW police cases of possession or supply of amphetamines are up 6.4 per cent in the year to March 2014. Drug Squad commander Tony Cooke attributes the rise, in part, to increased use of crystal methampthetamine and to police activity. "This drug is used across the community and the impacts are disastrous," he says.

Wran, 26, was reportedly "numb on ice" and living rough, often disappearing for weeks and surviving on Centrelink payments but still wearing expensive fur coats. Carroll described last year how ice made him evasive and erratic. "I became utterly powerless ...There was no gap between thought and action."

Alex Wodak, former director of the Alcohol and Drug Service at St Vincent's Hospital, says there has been a long-term trend towards increased stimulant use in Australia. 

The proportion of illicit drug users who say ice is "very easy" to obtain increased from 31 per cent in 2004 to 42 per cent last year, according to the National Drug and Alcohol Research Centre. As purity has increased, so has the median price of the drug, from $50 for a point (0.1 grams) in 2010 to $100 last year. 

Much of this is smuggled into Australia from countries such as China. The number of detections at the Australian border of amphetamine-type substances is the highest on record, increasing 85.8 per cent in 2012-13.

The number of amphetamine users being admitted to hospital is also on the rise. Possible health problems include sleep disturbances, weight loss, epileptic seizures and abnormal heart rhythms. 

But the potential mental health impacts are greater still, Dr Wodak says. "Not everybody who uses large quantities of amphetamines develop problems, many don't," he says. Others become so drug-addled they slip free of their social anchors, falling out with employers, family and friends.

"Mental health problems include depression and feelings of despair and suicide," he says. "People can temporarily lose contact with reality."