Obesity and mixed features in bipolar disorder: A systematic review

There is some clinical evidence indicating that obesity may change the trajectory of individuals with Bipolar Disorder (BD) to having more mixed features, however, to the best of our knowledge, there are no systematic reviews investigating this relationship. Thus, this systematic review is aimed at describing the association between obesity and mixed features in BD, specifically whether obesity changes the trajectory of patients with BD to having a greater frequency of mixed features. A literature search was conducted on October 22, 2021, using the following databases: PubMed, PsycINFO, and EMBASE. A total of 2 studies were included in this systematic review. Both studies described the frequency of mixed features in a population of patients with BD with and without the presence of obesity. Among individuals with BD, patients who were obese had a significantly greater probability of having mixed features than patients who were not obese. The prevalence of manic versus depressive or mixed mood states was significantly associated with obesity, since a higher percentage of patients who had BD and were obese presented with depressive or mixed mood states compared to patients who had BD and were not obese. Patients that are diagnosed with BD and present with obesity have a greater prevalence of presenting mixed features, which has been linked to worse clinical outcomes. More studies are needed to definitively determine the association between obesity and mixed features, and therefore, implement interventions to improve prognosis in patients with BD.