Impact of bipolar disorder on eating disorders severity in real-life settings

Background: Comorbidity of bipolar disorder (BD) and eating disorders (ED) is common and increases the course and severity of BD. However, the impact of comorbid BD on the clinical profile of ED patients remains unclear. Most studies have focused on patients primarily assessed for BD and data on patients with a primary diagnosis of ED are sparse. We investigated the association between a dual diagnosis and severity in terms of clinical, neuropsychological dimensions and daily functioning. Method: Two hundred and sixty-one patients with ED were consecutively recruited. BD was screened with the MINI and further confirmed in the French expert centre network. The severity of ED symptoms was assessed with the EDE-Q and EDI-2, daily functioning with the FAST. The neurocognitive assessment targeted attention, set-shifting and decision-making. Results: Forty-nine patients screened positive for BD, but diagnosis was confirmed in only thirty patients (11.5% of the cohort). After multiple adjustments, comorbidity was associated with greater severity on the total score and three subscales of the EDE-Q and on four of the ten dimensions of the EDI-2. Comorbid BD was associated with lower daily functioning but not with lower neuropsychological performance. Limitations: Sample referred to specialist clinics not large enough to authorize an analysis by subtype and cross-sectional evaluation. Conclusion: The association between ED and BD increases ED severity for most of these core features. It negatively impacts daily functioning. The results also highlight issues about the validity of screening tools to detect BD in patients with ED.