Diabetes mellitus is a severe chronic life-long disease. The condition itself introduces a need for patient's lifestyle adjustment to the disease and a number of everyday therapeutic and diagnostic restrictions. Therefore, mental disorders are more common in diabetic patients than in the rest of the population. Biochemical and hormonal connections between mental disorders and diabetes mellitus represent another reason for their higher incidence in diabetic patients. Comorbid mental diseases can further negatively influence the course of diabetes. They are especially depression, anxiety disorders, eating disorders and cognitive disorders including dementia. Type 2 diabetes is also more common in patients with primary mental disease, as is e.g. schizophrenia and bipolar affective disorder. Regarding therapy, psychoactive drugs are used in diabetic patients. It is important to respect the specifics of the underlining disease during drug selection. The main factor for the selection of the medication is, apart of mental problems, the influence on body weight and blood glucose. Mental disorders can be also treated by psychotherapy and psychoeducation. Studies performed in diabetic patients with mental problems suggest the need for intervention in this area. The practical part of the work introduces a...