Clinical characterization of rapid cycling bipolar disorder: Association with attention deficit hyperactivity disorder

Background: Rapid cycling (RC) bipolar disorder (BD) is associated with more disability and worse global functioning than non-rapid cycling BD (NRC) and is understudied. This study aims to investigate clinical characteristics associated to RC in a Latin-American sample and secondarily, to generate a clinical model to test the likelihood of RC in BD. Methods: 250 BD patients were enrolled between 2007 and 2015. All patients met DSM-IV criteria for BD type I, II or NOS. The sample was dichotomized into RC and NRC subgroups, and compared in terms of socio-demographic and clinical variables by bivariate analyses. A binary logistic regression was performed to generate a model and explain variance associated with the likelihood of presenting RC. Results: Final sample included 235 patients, of which forty-four (18.7%) met RC criteria. When compared to NRC, a significantly higher proportion of RC patients were female (81.4% vs. 58.9% p = 0.006), BD type II (58.1% vs. 29.7% p = 0.002), presented more manic/ hypomanic episodes (43.6 +/- 35.8 vs. 12.8 +/- 58.9, p = 0.001), and had less psychotic symptoms (20.9% vs. 42.2%, p = 0.010). Attention deficit hyperactivity disorder (ADHD) was a significant comorbidity in RC (23.7% vs. 8.3%, p = 0.007). No differences were found in suicidality, mixed symptoms, and seasonal pattern. After logistic regression, variables significantly associated with RC were presence of ADHD (OR 4.6 [95% CI 1.54-13.93] p = 0.006) and female gender (OR 3.55 [95% CI, 1.32-9.56] p = 0.012). Limitations: It is a cross-sectional study. Conclusions: Findings suggest that ADHD comorbidity, and female gender are risk factors for RC in BD.