Drug abuse and mental illness have strong patterns of association. Drug-users commonly have symptoms of psychiatric disorders, particularly anxiety, mood disorders and depression. Heroin users may be particularly vulnerable to mental health disorders. Both drug abuse and mental illness are major contributors to the increasing level of suicide (and, or heroin overdose) among young people. Understanding the complex relationships between drug abuse, mental health and personal circumstance was the primary motivation for conducting this analysis.

This report investigates relationships between drug abuse, mental health and personal circumstance for 182 probable heroin users aged 15 to 30 from inner metropolitan Melbourne. Matching 'Pharmaceutical Benefits Schedule' (PBS) data was obtained for 106 individuals for the period from 1995 to 2001. Most respondents were unemployed and many lived in non-permanent accommodation. A third of respondents had a family history of heroin use, while a family history of prescription drug abuse was also common. Nearly all respondents used heroin, while benzodiazepines, stimulants and cannabis were used by most respondents. PBS rates averaged 13/ person/ year, with over half of these scripts being for benzodiazepines and other opioids.

The heroin users in this study reported high rates of hopelessness, depression, anti-social behaviour and self-harm. Nearly one-quarter of respondents had suffered a mental illness, but only a quarter of those had seen a mental health professional in the last month. The relationship between poor mental health and risk of overdose was supported by our study, however particular scales designed to measure mental health status failed to directly predict overdose history. Instead, heroin users with a history of overdose were characterised by the following features:

• Receiving more prescriptions for antidepressants and tranquillisers;
• Receiving more prescriptions for opioids but fewer prescriptions for benzodiazepines;
• Being dissatisfied with relationships and engaging in more anti-social activities;
• Being younger and male;
• Being less depressed on the Short Mood and Feelings Questionnaire; and,
• Having experienced a previous mental health episode.

A history of mental illness also related to poor social support, including living alone or in temporary accommodation. Heroin users who reported a prior mental illness were more likely to be female and to have tried to harm themselves in the last six months.

The association between prescriptions for antidepressants and tranquillisers and a history of overdose suggests that general practitioners are identifying and treating patients for depression. Prescriptions for opioids other than benzodiazepines were also associated with overdose risk, perhaps because of their association with poly-drug overdoses. In contrast, benzodiazepines prescriptions are associated with fewer past heroin overdoses, perhaps because they are commonly used as a heroin substitute or to support withdrawal.

These results suggest that interventions offering improved social support for heroin users may reduce the incidence of depressive symptoms, as well as the risk of overdose. Encouraging general practitioners to continue and expand their recognition and treatment of depression in heroin users may play an important role in reducing heroin overdoses.

Recommendations

• Identification of risk factors; and,
• Further research into overdose risk and depression.

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