The difficulties of diagnosis and clinical differentiation of bipolar disorders, schizophrenia and schizoaffective disorder have been repeatedly noted both foreign and Russian authors.

Full medico-psychological service clinical documentation research, including bipolar disorder patient records.

Determination of bipolar disorders in accordance with the DSM-5 criteria among psychiatric outpatients.

A group of 142 patients with established according to ICD-10 diagnoses: schizophrenia, schizoaffective disorder 137 (96.5%); the average patient's age 50±13 and bipolar disorder and mania episode 5 (3.5%) – 55.4±14.4 has been investigated.

It was found that 18 (12.7%) of all patients meet the DSM-5 bipolar disorder criteria compared with the primary diagnosis (3.5%). Structure of the diagnosis of bipolar disorder was represented as follows: bipolar disorder type I – 11 (61.2%), bipolar disorder type II – 7 (38.8%). Consequently, due to formal application DSM-5 bipolar disorder criteria BD determination 3.5 times more.

Traditionally, the diagnosis of schizophrenia is preferred over bipolar disorder. Manic episode in bipolar disorder can be evidently regarded as an acute schizophrenia manifestation. The diagnostic criteria for DSM-5 are convenient in diagnostics of manic and depressive episodes in case of their combination in I type bipolar disorder.