Any addiction, whether alcohol or psychoactive substances has a devastating effect on a person's cognitive, physical and social abilities. The beginnings of alcohol and drug consumption occur for various reasons and as a result of the frequent use, addiction is created which is characterized by a changeing behavior, loss of social contact and psychophysical deterioration of the person. There is factors lead to poor quality of life which is one of the main drivers of abstinence and treatment whose consistency ultimately results in a better quality of life. The aim of this study was to determine that there are no differences in behavior and functioning between alcoholics and psychoactive substance addicts and that quality of life and psychosocial functioning are equally poor in alcoholics and psychoactive substance addicts. There search was conducted at the Clinic for Psychiatry of the Clinical Hospital Center Rijeka in an outpatient program that includes daily therapy of alcoholism and other addictions, the Club of Treated Alcoholics (KLA) at the Clinic for Psychiatryan and out patient clinic for alcoholism and other addictions. Through the collected data of this research, known facts about the patterns of behavior of the groups of addicts as well as knowledge about other factors that affect the psychosocial functioning of addicts it is concluded that in cognitive, physical and social functioning of individuals from these two groups there are no significant differences. The “common denominator” of their problem is poor quality of life which can be both a trigger and a result of addictive behavior.