Diving deeper to measure the toll of ‘ice’ on mental health

Methamphetamine (“ice”) use is a major public health issue in Australia – the most recent large-scale survey, in 2019, estimates more than 1.3 million people older than the age of 14 had used some form of it in their lifetime.

It’s also important to note that use of methamphetamine is generally higher in rural parts of Australia than in metropolitan cities.

Then, if we look at mental health, and the link between the two, we find that 13% of Australians have an anxiety disorder, and 10% have symptoms of depression. These disorders commonly co-occur, and the risks for experiencing either disorder are very similar.

The third-most common mental health disorder in Australia is substance use conditions, and commonly co-occur with anxiety and depression.

But much of the research regarding methamphetamine use and mental health outcomes has focused on the risk of experiencing psychosis, and experimental studies have shown “ice” can induce psychosis.

The evidence regarding depression and anxiety and methamphetamine use is much less conclusive, although previous data, including from the Australian Institute of Health and Welfare (AIHW) report cited above, suggests rates of depression and anxiety occur more frequently in methamphetamine users than in the general population in Australia.

Additionally, a systematic review, led by Rebecca McKetin of the Centre for Mental Health research at the Australian National University, found evidence of an association between methamphetamine use and depression, but no evidence of a link with anxiety disorders.

The most commonly reported form of methamphetamine used in Australia is the crystal form – ice – which is usually ingested through smoking. The social costs of methamphetamine use in Australia are overwhelmingly linked to crime, including policing and the justice system. The estimated costs of premature mortality and workplace impacts are also high.

Methamphetamine use is attributed to significant global disease burden, and is associated with high levels of health service use. Health problems arising from methamphetamine use include cardiovascular disease, renal issues, oral health, elevated risk of stroke, and significant psychological harm.

Nearly 1.5% of those surveyed for the AIHW reported using methamphetamine within the past 12 months.

With all this in mind, we wanted to study, more comprehensively, prevalence rates of moderate to severe anxiety and depression in a large cohort of methamphetamine-using participants, and to examine whether the experience of moderate to severe anxiety and moderate to severe depression were associated with specific demographic, socioeconomic, substance use, or other social and health factors.

An 850-strong collaborative study

The current study is embedded within Monash’s VMAX study, a project between the Burnet Institute and Monash Rural Health. It involves more than 850 community-based individuals across metropolitan and rural Victoria who use methamphetamine. Participant recruitment has been network-driven and through snowball sampling (where one participant helps recruit another).

All were over 18 and had used methamphetamine at least monthly in the past six months, and were primarily using non-injecting methods of administration.

We found that 60% of the VMAX cohort scored in the moderate to severe range for anxiety or depression.

The proportion of participants experiencing moderate to severe depression or anxiety was higher than Australians in the general population who had anxiety or depression. By far the majority of the sample were dependent, male, non-Indigenous, lived in either a metropolitan city or large rural town, and were unemployed.

It’s important interventions and services are responsive to clients’ needs related to depression or anxiety, as well as their methamphetamine use.

When we analysed demographic, socioeconomic, substance use patterns, and other health and social factors related to anxiety and depression in methamphetamine users, we found that poor or very poor self-rated health, methamphetamine dependence, and being unemployed were associated with higher odds of experiencing moderate to severe anxiety or depression.

Living in a large rural town, identifying as Aboriginal and Torres Strait Islander, and smoking methamphetamine were associated with lower odds of experiencing moderate to severe depression.

Being female was associated with higher odds of experiencing moderate to severe anxiety.

These findings highlight that health services are likely to encounter high levels of depression and anxiety among people who use methamphetamine compared with the general population.

Health services play an important role in the management or referral for the treatment of mental illness. Diagnoses of anxiety or depression may provide a segue into an integrated model of care whereby common co-morbidities can be treated.

Integrated models of care allow for a “no wrong door” approach that allows increased opportunities for individuals who use methamphetamine to seek professional support for their mental health.

Therefore, it’s important interventions and services are responsive to clients’ needs related to depression or anxiety, as well as their methamphetamine use.

Little focus on the non-injectors

There’s another important consideration for examining depression and anxiety in methamphetamine users. Very few studies have examined these associations in people recruited from non-treatment or non-custodial settings, or in those who primarily use non-injecting methods of administration, such as smoking, snorting, “shelving” (inserting the drug into the anus), and orally.

By and large, earlier research has recruited participants from within healthcare settings such as rehabilitation centres or safe-injecting rooms. Recruitment via these settings may be less problematic; however, it’s also been suggested that people who engage in treatment for their methamphetamine use are likely to have different characteristics compared with those who don’t seek treatment.

---

Read more: Reassessing the social context of illicit drug use and addiction

---

Further, those in treatment for methamphetamine use tend to have longer histories of illicit substance use in general, and are more likely to administer by injection. This is problematic, as mentioned earlier, because the majority of people who use methamphetamine are more likely to use non-injecting methods of administration,

Little attention to anxiety

Another important contribution the present study makes to the literature are the findings relating to anxiety. While co-morbid anxiety is commonly associated with other types of substance use disorder, the association between methamphetamine use and anxiety has received scant attention.

Importantly, our study also highlights the association between anxiety and depression in those who smoke methamphetamine. This has been a previously neglected area of research in Australia.

The findings of our study are consistent with the high prevalence of anxiety and depression found in people who inject methamphetamine. While the odds for experiencing moderate to severe depression were lower for smokers in the present study, the prevalence of anxiety and depression in this cohort is elevated relative to the general population.

It’s important that further research regarding methamphetamine smokers investigates the concurrent relationship of anxiety and depression, as well as anxiety independently.