[Frequency of bipolar affective disorders among depressive outpatients treated by psychiatrists].

Aim: To assess the frequency of bipolar disorders among outpatients with affective illness treated by 96 Polish psychiatrists, representing all regions of Poland.
Methods: The study was performed on 880 patients (237 male, 643 female). They were identified, according to the criteria used, into the following diagnostic categories: 1. Bipolar affective illness, type I (Bipolar I); 2. Bipolar affective illness, type II (Bipolar II); 3. Bipolar spectrum disorder; 4. Unipolar affective illness.
Results: Affective disorders having bipolar features were found in 61.2% of the patients studied, bipolar I more frequent in men (27.4% vs 17.6%) and bipolar II more frequent in women (31.7% vs 21.5%). Bipolar spectrum was identified in 12% of the studied patients. Patients with bipolar affective illness compared with unipolar affective illness had a family history of bipolar disorder significantly more frequently, premorbid features of hyper- or cyclothymic personality, early onset of depression (before 25 years), symptoms of atypical depression (hypersomnia and hyperphagia), episodes of psychotic depression, postpartum depression, and treatment-resistant depression. The group of bipolar spectrum had most clinical features similar to classic types of bipolar affective illness and showed significant differences with unipolar affective illness.
Conclusions: In outpatients, who had a depressive episode in the past and were treated by psychiatrists in Poland, bipolar disorders may amount to 60% of them. Patients with bipolar affective illness significantly differ from patients with unipolar affective illness as to the numerous clinical features, not connected with manic, hypomanic or mixed states. The results of the study may also indicate a legitimacy to delineate a bipolar spectrum disorder.