The criteria for the diagnosis of alcohol use disorders according to the DSM-5 classification concern many areas of human functioning and are part of the generally accepted biopsychosocial context, which is reflected both in the diagnostic as well as in the treatment process. Assessing the severity of the alcohol use disorder (AUD) and its mechanisms is crucial for setting objectives and implementing a targeted psychotherapy. The State Agency for the Prevention of Alcohol-Related Problems recommends therapeutic programmes aimed not only at abstinence but also at reducing drinking. Therefore, programmes of the detoxification treatment system in Poland are dedicated to people with diagnosed severe, moderate, and mild AUD. The aim of the article is to present diagnostic criteria for alcohol use disorders according to the DSM-5 classification. Detailed attention has been paid to the clinical picture of alcohol use disorders and the complexity of its biopsychosocial mechanisms. Also considered are suggestions for diagnostic questions and answers that can make it easier for professionals to assess the AUD and determine the direction of psychotherapy.