The aim of the TREAT-study (Treatment-systems Research on European Addiction Treatment) is the comparison of the course of predominantly opiate dependent patients from six European regions concerning severity of illness, health service use and heroin-use.
Method:TREAT is a collaborative multi-centre-study conducted in Athens, Essen, London, Padua, Stockholm and Zurich which includes three repeated measures over a period of 18 month (T1-T3). Apart from the Europ-ASI, questionnaires for comorbid disorders and the utilisation of the treatment system were administered. The sample comprised about 100 subjects per region diagnosed with opiate addiction. 317 patients (53%) were retrieved for all three measures.
Results:With some exceptions in all centres health service use by patients could be increased during the observation period. The severity of addiction decreased in almost all regions.
In a statistical model comprising all subjects who completed the study, the best predictor for abstinence was the number of detoxification treatments but also participation in long-term rehabilitative therapy. Patients with additional severe alcohol consumption at the beginning of the study had a higher risk for continuous drug use.
A second regression-model assumed that participants who had dropped out were still dependent on opiates. Again the combination of heroin and alcohol appeared to be a negative predictor. Patients in methadone maintenance treatment suffering from major depression showed a more positive outcome.
Discussion:Regional differences concerning patients´ characteristics, health services and drop-out rates give reason for a cautious interpretation. The study describes high- and low-risk-groups as hints for the effective allocation of resources.