[Comorbidity patterns and structure of depressive episodes in patients with bipolar disorder and major depressive...

To conduct an exploratory analysis of comorbidity patterns and the structure of depressive episodes among Russian patients with bipolar disorder (BD) and major depressive disorder (MDD).

This multicenter cross-sectional study included 178 patients with mood disorders, of which 78.1% (n=139) were women. The diagnosis of BD was made in 68.0% (n=121) patients, of them 37.1% (n=66) were diagnosed with BD type I. All study participants underwent a structured Mini International Neuropsychiatric Interview to verify the clinical diagnosis and identify concomitant mental disorders, and also filled out an electronic case report form. Statistical analysis was performed in RStudio v. 1.4.1717 using the standard R package and the «psych» package.

According to the results of stepwise regression, comorbid diagnoses of panic disorder (OR=5.3; 95% CI 1.9-19.1) and eating disorders (OR=7.7; 95% CI 2.8-27.4) were more associated with BD. In addition, depressive episodes in BD were more associated with symptoms of hypersomnia (OR=2.5; 95% CI 1.2-5.3) and psychomotor retardation (OR=3.2; 95% CI 1.5-7.6). Symptoms such as increased appetite (47.1% (n=57) vs 26.3% (n=15); p=0.009), ideas of guilt (92.6% (n=112) vs 7.2% (n=44); p=0.006) and thoughts of self-harm or death (70.2% (n=85) vs 45.6% (n=25); p=0.003) were also nominally more common in depressive episodes within the BD compared to MDD.

Mood disorders such as BD and MDD have significant differences in the patterns of comorbidity and the structure of depressive episodes, which is important to consider when conducting differential diagnosis of these disorders. The results also indicate the need for a comprehensive diagnostic interview with patients with mood disorders to assess the presence of comorbid mental disorders during life and the structure of depressive episodes throughout the clinical course from the moment of onset.