Psychiatric comorbidities in bipolar disorders: An examination of the prevalence and chronology of onset according to sex and bipolar subtype

Objectives: Bipolar Disorder (BD) is frequently comorbid with other psychiatric disorders. However, few studies systematically examine which disorders are more likely to occur pre- or post-BD onset. We examine the prevalence and Age At Onset (AAO) of psychiatric conditions in adults with BD. Methods: A structured clinical interview was used to assess lifetime history and AAO of alcohol and cannabis misuse, suicide attempts, anxiety and eating disorders in a French sample of euthymic patients with BD (n = 739). Regression analyses were used to test for statistically significant associations between rates and AAO of comorbidities in BD groups stratified by sex or subtype. Results: Prevalence of alcohol and cannabis misuse was associated with male sex and BD-I subtype; whilst most anxiety and eating disorders were associated with female sex. The AAO of most comorbid conditions preceded that of BD, except for panic disorder, agoraphobia and alcohol misuse. Few variations were observed in AAO of comorbidities according to groups. Limitations: All assessments were retrospective, so estimates of prevalence rates and especially exact AAO of some comorbidities are at risk of recall bias. Conclusions: Sex and BD subtype are associated with different rates of comorbid disorders. However, there were minimal between group differences in median AAO of comorbidities. By describing the chronological sequence of comorbidities in BD we were able to demonstrate that a minority of comorbidities typically occurred post-onset of BD. This is noteworthy as these disorders might be amenable to interventions aimed at early secondary prevention.