Mixed Features: Challenges in Diagnosis and Treatment

Mixed states in bipolar disorder involve the coexistence of manic and depressive symptoms, either fully meeting diagnostic criteria for both or presenting as subthreshold features. Historically described by Kraepelin as severe mood dysregulation, mixed states were poorly integrated into earlier diagnostic frameworks. Narrow criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV and the International Classification of Diseases (ICD)-10 defined mixed episodes as rare conditions requiring full criteria for mania and depression. However, evidence shows subsyndromal mixed features are common and significantly affect prognosis and treatment response. The DSM-V introduced the “with mixed features” specifier, broadening the concept to include mania- or depression-predominant episodes with opposite polarity symptoms. Clinically, mixed mania features dysphoria, anxiety, guilt, and suicidality, while mixed depression shows irritability, distractibility, and psychomotor activation. Non-mood symptoms, such as anxiety, psychosis, and behavioral dysregulation, heighten suicide risk. Treatment remains challenging due to limited evidence, mostly derived from post-hoc analyses of atypical antipsychotics, including asenapine, olanzapine, quetiapine, lurasidone, cariprazine, and lumateperone. Robust randomized trials are scarce. Mixed states remain diagnostically and therapeutically complex, requiring refined criteria, deeper pathophysiological understanding, and individualized treatment strategies.