Diploma thesis title: Depression and addiction diseases Objective: The aim of this study was to examine whether there are differences between the group of patients suffering from depression and addiction and the group that has other psychiatric comorbidities in addition to depression and addiction. Materials and methods: We retrospectively analyzed medical records of patients suffering from depression and addiction treated at the Department of Psychiatry, University Hospital of Split from January 1ˢᵗ 2018 to January 1ˢᵗ 2020. Data were collected for: gender, age, number of hospitalizations, heterodestructiveness, self-destructiveness, age at first contact with psychiatrist, duration of drug consumption, socioeconomic status as well as somatic and psychiatric comorbidities. Results: The study included 47 patients. 17 of them suffer from depression and addiction and they form a control group, and 30 in addition to the above two have other psychiatric comorbidities and they form a test group. In both groups, the majority of respondents are middle-aged males. A significantly higher number of suicide attempts was proven in patients of the control group where 64.71 % tried to commit suicide than in the test group where 26.67 % of them tried to commit suicide. No statistically significant difference was found between the groups in the number of suicide attempts in relation to marital status. There is a difference in the number of suicide attempts in relation to the working status between the groups. The highest number of suicide attempts was found in the unemployed patients of the control group, while the lowest number of suicide attempts was found in the employed patients of the test group. There was no statistically significant difference in the number of hospitalizations between groups in relation to the existence of somatic comorbidity. The mean number of hospitalizations in both groups was 3. Conclusions: In this paper, we have pointed out the problem of suicide among this group of patients and the risk factors such as unemployment and single life. Further efforts by medical staff are needed to identify depression and substance abuse as soon as possible. Early recognition and treatment can avoid further complications and worsening of the patient's condition. Further research is needed to determine additional differences between these groups of mental patients.