By using multipliers for the data based on population numbers, the researchers found that, in 2013–14, there were 268,000 regular methamphetamine users and 160,000 dependent users aged 15 to 54 years in Australia.
“This equates to population rates of 2.09% for regular and 1.24% for dependent use,” the study said.
“The rate of dependent use had increased since 2009–10 [when the rate was estimated to be 0.74%] and was higher than the previous peak [1.22% in 2006–07]. The highest rates of use were consistently among those aged 25–34 years.
“It is also important to note the recent increase in estimated dependent use among those aged 15–24 years: in 2012–13, the rate was estimated to be 1.14%.”
The findings contradict recent reports. Until now, reports have indicated that methamphetamine use has remained stable in Australia since 2001 but that there had been a significant shift in use from the powdered form of the drug, known as speed, to the more potent crystallised form known as ice, leading to greater harms.
The Medical Journal of Australia study said regional areas may be driving the increase the researchers found. Initially, new users of the drugs may report extremely rewarding effects, which they then share with their friends, leading to more new users, the study said.
This was often followed by “a swift development of problem use among heavy users”, the study found, who may develop problems such as psychoses and dependence, or who may be arrested for drug possession and supply.
“The emergence of these problems produces a rapid decline in new recruits as the high visibility of these harms becomes apparent to non-using peers. Rapid uptake of methamphetamine use may still be occurring outside the largest cities, especially in regional centres where young people without prior experience of methamphetamine may be exposed to it.
The chief executive of the not-for-profit substance use research organisation the Penington Institute, John Ryan, said the study confirmed what front-line workers had suspected for some time but had been unable to strongly quantify.
“It certainly looks like regular and dependent use is increasing, and significantly, and that coincides what the community has been saying, particularly in regional areas,” Ryan said.
“The problem with illicit drugs is that it’s very much an underground act, and people don’t want to divulge their drug use, so the data has been really unclear. That’s why this is an important study and absolutely consistent with what people who respond to those affected by drugs, such as police and emergency workers, have been seeing.”
Addressing methamphetamine use meant getting the issue “out into the open”, he said.
“That means education campaigns around the drug must be fact-based, not fear-based,” Ryan said.
“Scare campaigns don’t work. We don’t do nearly enough to intervene with users early to prevent them from getting onto a trajectory that might lead to addiction and that’s because people are fearful of talking about their use.”
He agreed with the conclusion by the study that health services to address the health problems associated with regular methamphetamine use needed to be expanded.
“We can’t arrest our way out of this problem and drug seizures at borders still don’t really give us a good indication of how much is still getting through to the community,” Ryan said.
Degenhardt told Guardian Australia that there had been considerable discussion about whether increased concerns about methamphetamine use reflected the scale of the problem and whether the number of people using the drug has changed.
“Some have pointed to the fact that no increases have been detected in the proportion of people using methamphetamine at least once in the past year, as measured in Australia’s national household surveys,” she said.
“However, it is well-acknowledged in the illicit drug field that household surveys of the prevalence of less common and more stigmatised forms of substance use are likely to produce underestimates for several reasons. For example, people involved in heavier forms of illicit drug use may not live in traditional households included in the sampling frames, they may not be available or agree to be interviewed and they may not disclose use if they agree to be interviewed.”
It was unlikely the rise in users researchers had detected through their equation reflected an increase in use among existing users, she said.
“The strongest evidence for this in our estimates is the fact that we have seen increases in young people who by definition will largely be new to methamphetamine use.”