Differences in clinical presentation between newly diagnosed bipolar I and II disorders: A naturalistic study

This naturalistic clinical study aims to investigate differences between newly diagnosed patients with bipolar type I (BDI) and bipolar type II (BDII) disorders in socio-demographic and clinical characteristics, affective symptoms, cognition, functioning and comorbidity with personality disorders. The BD diagnosis and type were confirmed using the Schedules for Clinical Assessment in Neuropsychiatry. Affective symptoms were assessed with the Young Mania Rating Scale, the Hamilton Depression Rating Scale, the Major Depressive Index, and the Altman Self-Rating Mania Scale. Functional impairment was assessed with the Functional Assessment Short Test. Cognitive impairment was evaluated by the Screen for Cognitive Impairment in Psychiatry and the Cognitive Complaints in Bipolar Disorder Rating Assessment. Finally, comorbid personality disorders were assessed with the Standardized Assessment of Personality-Abbreviated Scale and structured interview Structured Clinical Interview for DSM-disorders. 383 newly diagnosed patients were included (BDI: n = 125; BDII: n = 258). Against expectations, we found no more depressive symptoms in BDII compared with BDI nor any differences in cognitive, childhood trauma or overall functional impairment. The only difference was lower occupational impairment in the BDII group. The self-reported measures of cognitive difficulties and childhood trauma involved potential bias (recall or other). Despite BD being newly diagnosed a diagnostic delay was observed. Patients newly diagnosed with BDII and BDI had similar burdens of depressive symptoms and cognitive and overall functional impairment, however patients with BDI had lower occupational functioning. No statistically significant difference was found in prevalence of comorbid personality disorders between patients with BDI and BDII. •Prevalence of depressive symptoms did not differ between patients newly diagnosed with BD I and II.•Cognitive impairments were similar in patients newly diagnosed with BD I and II.•Personality disorder prevalence was higher in patients with newly diagnosed BD II.•Similar functional impairments overall were found in BD I and II.•Patients newly diagnosed with BD type I had lower occupational functioning.