The propensity for addiction may be influenced by genetic inheritance and environmental factors such as different types of trauma and peer pressure. Nevertheless, some individuals who have a positive family history for developing alcoholism or who have been in traumatic settings, never develop an addiction, and, on the other hand, addiction can also develop in individuals who do not have these predisposing factors. Accordingly, an individual’s personality structure is a factor that plays a key role in the development of addiction. For the sake of analysis, the personality of an addict is observed through different theories, each of which has its own interpretation of that personality. Addicts often show characteristics of antisocial behaviour, impulsivity, and neuroticism. Although people who suffer from addiction share a lot of similar characteristics, the differences between individual types of addictions and the predisposing psychological structures of personality for each of them are quite large. Thus, alcohol addicts are more likely to be introverted, socially maladapted, and have low self-esteem. An important method of treatment for alcoholics is psychotherapy which can be used to identify the causes of addiction and provide appropriate emotional support to the patient. Discoveries about the personality of and addict can be used to develop effective prevention and intervention programs that can be tailored to an individual according to their type of addiction.