It was estimated that in general adult population represented in 2–3% co-occurring mental and substance use disorders.

In our case we represented the patient who is a long-time heroin addict with a dual diagnosis of bipolar disorder. Special attention was payed to influence of the primary psychiatric disorder to a course and treatment of substance abuse.

Patient is observed during the five years from March 2005 to March 2010. In the evaluation of the case we used History of illness, MINI, HAMD. and psychological tests battery (MMPI 202, Drawing Human Figure, EGO Perception and EGO Ideal Test).

During the observation we have noticed that the patient was started treatment in periods of depression decompensation, because of heroin relapse. In that moment HAMD score was between 20 and 24 points. After detoxification, the patient was experiencing a switch in hippomanic state, which resulted in drop-out in the first month of treatment. This course of disease was repeated five times during our observation. Because the patient retained in treatment, we were able to progress. Now, the patient has been in abstinence for eight months, and he is in acceptable affective stability.

Bipolar Disorder is increased risk for frequent heroin relapses and continuity in the therapeutic treatment. This influence may involve direct effects of drugs on the initiation of affective symptoms and indirect effects on treatment compliance. When symptoms are controlled through these psychiatric medications, patients will benefit from therapeutic treatment of their substance abuse.