The effect of body mass index on illness characteristics in patients with affective disorders: Results from an Italian multicentric study

Objective: Patients suffering from severe mental disorders have a reduced life expectancy of 10–25 years compared to the general population, mainly due to the presence of physical comorbidities such us metabolic disorders. This study aims to explore the relationship between BMI and several clinical and sociodemographic factors in a sample of patients with affective disorders. Methods: This is a naturalistic observational multicenter study carried-out in 7 Italian university sites. Patients aged 18–65 years with bipolar disorder (BD) or major depressive disorder (MDD), diagnosed according to DSM-5 criteria, and in a stable illness phase, were recruited. Affective temperaments were assessed with the Munster Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego; impulsivity with the Barratt Impulsiveness Scale; suicidal ideation with the Columbia Suicide Severity Rating Scale. Results: A total of 598 patients were recruited. According to the regression analyses, the likelihood of having a higher BMI was increased by a higher trait-related impulsivity (p < 0.05), higher number of lifetime affective episodes (p < 0.05), male gender (p < 0.01), a depressive affective temperament (p < 0.05), use of lithium and of other antiepileptic drugs (p < 0.05). Conversely, a higher educational level reduced the likelihood of higher BMI (p < 0.01). Conclusion: These findings highlight a strong link between BMI and impulsivity, number of affective episodes, temperament, gender and use of antiepileptics. Their routine assessment would be useful for an early identification of metabolic comorbidities and for the identification of patients at higher risk of having a worse physical outcome.