The study was on sample includes 50 addicts were selectively chosen during a period of at least one month free from acute intoxication or withdrawal symptoms, aiming to study the prevalence of positive and negative symptoms in drug abused patients, the role of these symptoms on the etiology of the drug addiction. The most prevalent substance was heroin, followed by bango, hashish, alcohol and others drugs. Most patients were positive subtypes, while negative subtypes were more clinically significant in spite of lower prevalence than positive and neither subtype. Comorbidity of other symptoms appeared also in the study as depression, anxiety, personality disorders and schizophrenia.