Executive Summary

Introduction
Heroin dependence is remarkably persistent and is, in many cases, a lifelong condition, yet the long term outcome following treatment for heroin dependence is rarely studied and has not yet been systematically studied in Australia. Better understanding of the long term outcomes in terms of mortality, drug use patterns, criminality and psychiatric comorbidity has the potential to guide more effective interventions and public health responses both nationally and internationally.

The Australian Treatment Outcome Study (ATOS) is the first large scale longitudinal treatment outcome study of persons with heroin dependence to be conducted in Australia. ATOS is coordinated by the National Drug and Alcohol Research Centre (NDARC), and is conducted in collaboration with the Drug and Alcohol Services Council (DASC) and Turning Point Alcohol and Drug Centre.

The aims of ATOS are:

To describe the characteristics of people seeking treatment for problems associated with heroin use in Australia;
To describe the treatment received; and
To examine treatment outcomes and costs at 3 and 12 months after commencement of treatment.

The current report presents combined 12 month data from New South Wales, South Australia and Victoria.

Method
Thirty eight treatment agencies were randomly selected from within the three main treatment modalities (methadone/buprenorphine maintenance therapy - MT; detoxification - DTX; residential rehabilitation - RR). Seven hundred and forty five individuals entering treatment and 80 heroin users not seeking treatment (NT) were recruited into the study and interviewed by trained research staff using a structured questionnaire. A total of 657 individuals were re-interviewed at 12 months, 80% of the original sample. Data was collected on a variety of domains including: treatment experiences; heroin and other drug use, mental health and criminal activity.

Results
Comparison of ATOS participants interviewed at 12 months and those lost to follow-up

There were no differences between those re-interviewed and those lost to follow-up in terms of baseline age, gender, treatment history, heroin use, criminal involvement, Major Depression or personality disorders, suggesting the sample re-interviewed is broadly representative of the original cohort.

Treatment exposure among the NT group

74% of the NT group had received some form of intervention for their heroin dependence since baseline. However, the important predictor of positive outcomes at 12 months is the extent of treatment exposure in terms of the cumulative number of days spent in treatment over the 12 month follow-up period. The NT group experienced significantly fewer total treatment days than the index treatment groups groups.

Heroin and other drug use

There were substantial reductions in heroin and other drug use across all three treatment groups. The majority of those who had entered treatment were abstinent from heroin in the month preceding the 12 month follow-up interview (MT 65%, DTX 52%, RR 63%). While there was also an increase in one month abstinence in the non treatment sample, this was considerably less at 25%.
The reduction in heroin use in the treatment samples was paralleled by reductions in the use of other drugs, suggesting individuals were not substituting heroin use with other drug use to any significant degree.

Criminality

There was a notable reduction in the proportion of participants committing crime or obtaining their main source of income through crime across the treatment samples.

Injection-related health and risk-taking

There were improvements in injection-related health across all treatment modalities, but a less marked improvement among the non treatment group.
There were reductions in injection-related risk taking behaviours across all treatment modalities.

Major Depression

The prevalence of Major Depression declined across all treatment modalities. The important treatment factor associated with reduced depression was stability of treatment, with fewer treatment episodes over the follow-up period being associated with less likelihood of having Major Depression at 12 months.

Conclusion
The high rate of sample retention at 12 months is of an international standard and lends validity to the findings. The study indicates that heroin users can be successfully engaged in longitudinal studies. There were substantial reductions in drug use, risk-taking, crime and injection-related health problems across all treatment groups and less marked reductions among the NT group. Psychopathology was also dramatically reduced among the treatment modalities, while remaining fairly stable among the NT group, perhaps due to their lower baseline levels. The important treatment factors associated with positive outcomes at 12 months were the cumulative number of treatment days experienced over the 12 month follow-up period (‘treatment dose’) and the number of treatment episodes undertaken in that time (‘treatment stability’). Overall, at 12 months the general functioning of all groups had substantially improved since baseline.

Citation: Ross, J., Teesson, M., Darke, S., Lynskey, M., Ali, R., Ritter, A. and Cooke, R. (2004) Twelve month outcomes of treatment for heroin dependence: Findings from the Australian Treatment Outcome Student, Sydney: National Drug and Alcohol Research Centre.