The authors present the results of the assessment of 211 forensic psychiatric expert opinions, where the use of addictive (psychoactive) substance was a reason for rendering a decision on examination of the mental state. The aver age of the whole group was 23.79 years, with men prevailing. The women represented 22.63 % of the group. The most frequent type of addictive substance, the use of which was related with the criminal activity, were the opioids (159 probands). Alcohol was the “main” narcotic in 43 probands. Other psychoactive substances, the use of which was related to criminal activities, were rare. In probands using heroin, the most frequent criminal acts were stealing property (83.64 %), alcohol was mostly connected with violence and extreme violence (58.13 %). The relation between using heroin was usually motivating - raising money for buying the drug. Criminal acts related to alcohol were committed most of ten during intoxication (76.74 %). From among other criminal acts, the most frequently found were the personality disorders. The so-called genuine mental disorders (neurosis, psychosis) were found in 6 probands only, however, the psychotic disorders had material impact on the conclusions of the opinions and the assessment of self-control and consciousness.

Key words: addictive substances – alcohol – heroin – forensic experience