In a 5-year-follow-up study of 350 opiate addicts in contact with a drug help system in Hamburg, 272 clients (78%) were interviewed a second time after 1 year. The objective of the study was to examine the correlation between mental disorders and drug consumption and its relationship to clients' general life situation. In the majority of the opiate addicts, a pattern of polydrug consumption was observed, but the amount of drugs consumed was clearly lower after 1 year. In the initial survey, a mental disorder according to ICD-10 could be diagnosed for 55% of the sample. Among groups formed by the severity and course of mental disorders or their symptoms, a significant correlation was observed, particularly at the time of follow-up, between the extent of drug consumption and the course of the mental disorder. Other areas, like physical health or social problems/conflicts, were also related to comorbidity (i.e., heavy drug consumption and/or mental disorder). These interrelationships should be taken into account in treatment, care and guidance to increase the prospects for successful treatment.