Methamphetamine use in Australia
Who uses meth
There is no class-related pattern to methamphetamine use in Australia. Users come from all walks of life. It is rare for people under 19 to use the drug, but use jumps markedly among people in their twenties. The highest rates are between 20 and 29 years of age, with rates reported as high as 6% in 2010–2011.
Use has generally grown, although the rate among people in their twenties has fallen from a 2007 peak of 7.3%, with the difference made up by a rise in older and younger users.
Unlike many other drugs, methamphetamine use is higher among people in paid employment. It tends to be higher in certain industries: notably hospitality (6.1%), sex workers (variable rates reported), construction (5.5%), media (5.0%), mining (4.4%) and the financial sector (4.0%). Use is also higher among fly-in fly-out (FIFO) workers, especially at mines or offshore industrial sites, and among long-distance drivers and single men, as well as among gay men.
Use among men is higher than among women, but the difference is smaller than for many other drugs.
Types of meth
Methamphetamine comes in a variety of forms, most commonly speed (powder or pills), crystal meth or ice (crystal methamphetamine), and ‘base’ (a sticky paste).
In its pure form it is a white, odourless crystalline powder that dissolves readily in water. As ‘ya-ba’ it may be brightly coloured and often candy or fruit flavoured to increase its appeal.
Most users prefer the cheaper, lower potency speed powder or pills, which can be snorted, swallowed or injected. A small but growing number of people inject or smoke crystal methamphetamine, which is the most potent form, up to 15 times more potent than pure amphetamine by weight. Crystal meth (ice) can be used on its own but is often laced with other drugs, most commonly ecstasy or cannabis.
The effects
The great majority of methamphetamine users use the drug infrequently and in relatively low doses. The problem is that methamphetamine is addictive, and crystal meth extremely so. On average, around 10 to 15% of methamphetamine users develop a serious dependence that requires intervention, and the rate is substantially higher for crystal meth.
Methamphetamine has a chemical structure similar to dopamine, the brain’s ‘feel good’ neurotransmitter, which regulates the reward system, motor control and cognitive processes. Taking methamphetamine forces the brain to release large amounts of dopamine, over 1000 times the normal level. This produces distorted feelings of intense pleasure and euphoria that can initially last an entire day. The effect is substantially higher than the dopamine surge from sex or other common pleasures. The ‘rush’ usually begins within 5 to 30 minutes of use and, in the early stages of use, may last up to 16 hours.
Intense pleasure is not the only effect. Methamphetamine also disturbs the judgement centres of the brain, disordering activity in the prefrontal cortex that regulates emotional impulses and keeps behaviour socially appropriate. It triggers the release of noradrenaline, leading to heightened aggression and jumpiness or hypervigilance, from inappropriate activation of the ‘fight or flight’ reflex. The judgement of regular users is often impaired. They are often aggressive and occasionally paranoid, and usually show grandiosity and blindness to risk.
The highs are only temporary. The ecstatic high comes from a sudden emptying of the local dopamine stores, so the pleasure ends and is followed by a crash marked by exhaustion, irritability, severe fear and panic, and a strong desire to take methamphetamine again.
This phase of withdrawal is marked by a slow progression to deep depression (usually described as worse than with cocaine), lethargy, cravings and disrupted sleep. Insomnia is usual, although over-sleeping with vivid nightmares may occur. Many users drink heavily at this time, or take benzodiazepine sleeping pills or cannabis to deal with the insomnia.
The costs
Even among infrequent users, methamphetamine is a dangerous drug. Severe vascular damage has been reported among injecting users, and there is a significant risk of rhabdomyolysis (‘muscle meltdown’) at higher doses. Chronic users often grind their teeth uncontrollably, causing marked damage, and at any dose methamphetamine can lower the seizure threshold and lead to fits.
There is a high risk of uncontrolled aggression. At high doses methamphetamine may induce a severe psychosis with extreme paranoia and often bouts of self-mutilation, as users try to dig out bugs they imagine are crawling under their skin. These psychotic episodes can be extremely difficult to treat, and around 5 to 15% of chronic users currently fail to recover from them.
Regular use, even at relatively low doses, will slowly destroy the dopamine-producing neurons in the brain, so the brain is unable to produce enough dopamine to function normally. Over time, a user needs higher and higher doses to get the easy high of their early use. When users stop after a long period of use, they tend to be depressed and lack motivation. Strong cravings are common, especially for sugary foods, because they are incapable of feeling pleasure from much else.
Unlike common amphetamine, methamphetamine is a neurotoxin (to dopamine-secreting neurons), so users have an increased risk of developing Parkinson’s disease.
Managing someone affected by methamphetamine
Dealing with someone acutely affected by methamphetamine is difficult. Trying to restrain them or get them to calm down often makes aggression and anxiety worse, especially during a bout of drug-induced paranoia. The best immediate response is to calmly move the person to a quiet spot away from harm and distracting stimuli.
Long-term users often appear flat and unmotivated, but they are often subject to strong cravings that make a relapse very likely. Treatment programs are slow and often involved, but benefit greatly from the support of family and friends. The changes caused by methamphetamine usually lessen in time, but it can take up to a year before a regular user feels normal again.
Drug testing
Methamphetamine can be detected in both saliva and urine. In saliva (oral fluid), use can be detected up to 12 to 16 hours after use. In urine, use can be detected more than 2 days after infrequent use, and nearly 4 days after chronic use.
Drug tests work on a basic two-level system. The initial tests, which identify the possible presence of a class of drugs, are immunoassay screening tests. They are very sensitive but not absolutely specific, which means they can give false positives. Some drugs may cause a false positive for amphetamines on screening tests, including:
- prescription amphetamine prodrugs, including selegiline
- over-the-counter nasal decongestants, including Vicks (including Vapoinhaler).
A person about to undergo drug testing should give the collector a full list of all the medicines and supplements they are taking, to avoid misunderstandings.
If a positive result is obtained, the sample is then subject to a confirmatory GC/MS or LC/MS test, which is absolutely specific.
Source: Safe Work Laboratories.