Abstract
An investigation into the ability to drive of patients undergoing methadone treatment is described. The study examined both psychomotor skills and resistance to drugs by means of laboratory testing, driving performance and anamnesis. An additional test was carried out to prove the thesis that there is comorbidity between addiction and other non-psychotic psychic diseases, especially neuroses and personality disorders. The results showed few differences between the patients and the control group. The main finding of the research was the significant level of relapse to drug abuse and a lack of motivation to end the addiction.