Methamphetamine – the impacts and an emerging treatment

Methamphetamine dependence is a growing public health concern in Australia and around the world.^1,2 The health concerns are linked to multiple aspects of a person’s life, including their physical and psychological health, impacts on schooling and work, personal relationships, and in the broader community.²

As we learn more about the impacts of methamphetamine use around the world and in Australia, researchers are looking for ways to treat those who are dependent. We consider the statistics, why methamphetamine dependence is so harmful and difficult to stop, and an emerging treatment for people with a dependence.

Methamphetamine use in Australia

Methamphetamine belongs to a wider class of drug called amphetamines and can come in different forms, including crystal methamphetamine (also known as ‘ice’).³ It is quite common for ice-use to be reported as part of methamphetamine use in statistical reports. This means the use of ice has the potential to be reported in a way that seems greater than it is.

Understanding this distinction is important because ice is the stronger and more addictive form of methamphetamine, and so has the potential to cause greater harm for people who use it.

The 2016 National Drug Strategy Household Survey (NDSHS) estimated that approximately 0.8% of the Australian population had ever used ice.⁴ In the last 12 months, about 1.4% reported having used any kind of amphetamine, 57% of which preferred to use ice.⁴ While ice-use has decreased, when compared to 2016 data, we know that this figure is still almost double compared to 2011 data.^2,4

What this means is that although the use of ice is on the decline overall, it is causing a greater level of harm than it has in the past, emphasising the need for ongoing prevention efforts and research for effective treatment for dependence.

Based on a number of data sources, including the NDSHS and the National Wastewater Drug Monitoring Program, we know that methamphetamine use among people in rural and remote parts of Australia is higher when compared to people living in urban areas.² Additionally, young people aged 18-24 are more likely to use ice if they are from a rural or remote area compared to young people in urban areas.

Why is it difficult to treat ice dependence?

When someone takes a stimulant drug like ice, the messages travelling between the brain and the body increase and create a ‘high’. Dopamine is released as a part of this process, which is an important neurotransmitter associated with the regulation of reward in the brain. It is then blocked from being re-absorbed by ice, which prolongs the feelings of the ‘high’.⁵ The difference between ice and other illicit stimulants such as cocaine, is that ice has much longer action because it is metabolised slower and persists unchanged in the system for longer.⁵

Ice acts on two key functions regarding dopamine – it increases release and blocks the re-absorption. This has been shown to be toxic to the brain over a longer period.⁵

Ongoing, chronic use of ice has therefore been shown to have a lasting effect on the brain’s ability to produce and regulate dopamine levels.⁵ For people who have previously been dependent on ice and decide to stop, it can take a longer period for their brain to get used to functioning without ice. Their ability to regulate dopamine release and reabsorption will mean that they may not be able to feel good without using ice, which means that the cravings can be overwhelming during the withdrawal process, making relapse quite common.⁶

There are currently no medications available that are approved for treating withdrawal or dependence on methamphetamines, and so people who are trying to stop are solely relying on psychotherapy to get through the difficulties associated with what is in fact a change to their brain.

Ice dependence is therefore a highly complex health condition that has the potential to significantly affect a person’s day-to-day life in the longer term.¹

An emerging treatment

Australian researchers are currently leading a project to conduct a world first out-patient trial of a medication called N-acetylcysteine (NAC),⁷ which targets the changes that can occur in the brain of a person with drug dependence. NAC works in two ways – by protecting against methamphetamine related neurotoxicity that result in changes to the brain and therefore severe cravings, and the management of psychiatric symptoms.^{1, 7}

Previous randomised-controlled-trials have been completed to test the efficacy of NAC on treating methamphetamine dependence,⁸ however they have been limited by low participation rates, short-term trials, a lack of parallel psychiatric treatment for participants, and majority of previous studies have had varying research methods.⁸ This means that it has been difficult to generalise the potential efficacy of NAC due to the different ways that the treatment was applied in different studies.

The most recent Australian research supports previous findings, which appear to suggest that NAC has the potential to reduce cravings, and in turn reduce the risk of relapse.¹

The next phase of this research is underway, with a second, larger trial taking place between 2017-19.⁷ This work has the potential to significantly change the process of treatment for methamphetamine withdrawal and protect against the longer-term harms associated with multiple relapses.