Only limited information on the process of completing long-term opiate substitution treatment (OST) with substances like methadone exist. Furthermore, systematic knowledge from scientific studies is scarce, there are only few studies with respect to treatment completion or regular termination (mainly catamnestic analyses). Studies by Nordt et al. (2004) or Nordt & Stohler (2006) show an estimated rate of 10% of patients per year who terminate OST by means of tapering the substitution agent or changing into withdrawal treatment in specialized clinics. It is state of the art that an indication for termination of OST has to be based on a common agreement between the patient and the doctor. Furthermore, the patient should live in a stable social situation and the state of health had markedly improved. Finally, the patient has to be free of (illegal) drug use for at least 6 months and the individual aims of treatment should have been reached (Vader et al. 2003).

The main objective of the prospective and explorative study is the systematic description of the process of termination of OST. With a comparison between patients who complete OST regularly and patients who terminate treatment prematurely (or are still in treatment) predictors of positive termination of OST can be identified.

Patients treated with methadone or levomethadone of 5 general practitioners' practices and 2 specialized clinics who might be able to terminate OST during the next 12 months from the doctors' perspective can take part in the study. In addition to baseline examination further assessments take place every 3 months (i.e. after 3, 6, 9 and 12 months). The questionnaires include state of health, well-being, social situation as well as drug and alcohol use. Furthermore, the treating doctors are asked every 3 months to fill out questionnaires on infections and other disorders, clinical characteristics, dosage process and drug use (measured by urine samples).

Patients who will be successful in completing OST during the observational period will be compared with the remaining cases.

Finally, a 6-month follow-up is planned in order to investigate the stability and maintenance of the situation at month 12.

Inclusion Criteria:

• opioid dependence according ICD-10
• Minimum age of 18 years
• In OST with methadone or levomethadone
• Expected or planned treatment completion during the next 12 months
• Informed consent to participate in the study

Exclusion Criteria:

• Patients with planned hospitalisation during the next 12 months
• Patients who are likely or it is save to assume that they will be incarcerated or imprisoned during the next 12 months
• Disability to take part in the study or follow the study conditions

Patients in primary care setting (GPs) or specialized clinics likely to complete opiate substitution treatment (OST) during the next 12 months.

Patients treated with methadone or levomethadone who were eligible for the study and consented to participate and qualified for treatment completion in the next 12 months.