Management of Depressive Episodes in Bipolar Disorder: Clinical Risks, Evidence Gaps, and Strategic Use of Antidepressants

Bipolar depression represents a major clinical challenge due to its high prevalence, significant functional burden, and complex diagnostic and therapeutic considerations. Accurate diagnosis requires a structured approach that distinguishes bipolar depression from unipolar depression, incorporating clinical features such as atypical symptoms, family history, and illness course, as well as emerging neurobiological markers. Clinical phenotyping, including bipolar subtype and predominant polarity, plays a crucial role in guiding individualized treatment strategies and improving long-term outcomes. The neurobiological basis of bipolar depression is multifactorial, involving alterations in monoaminergic, glutamatergic, and GABAergic systems, as well as neuroinflammation, impaired neuroplasticity, and circadian rhythm dysregulation. These mechanisms contribute to both symptom development and variability in treatment response, supporting the need for integrative therapeutic approaches. Mood stabilizers and atypical antipsychotics remain the foundation of treatment, with agents such as lithium, lamotrigine, and quetiapine demonstrating efficacy in symptom control and relapse prevention. In contrast, the role of antidepressants remains controversial. Although they may offer modest benefits in selected patients, particularly as adjunctive therapy, their use is limited by the risk of manic switching, rapid cycling, and mood destabilization. Current evidence from clinical trials and meta-analyses is inconsistent and often limited by methodological heterogeneity. Non-pharmacological interventions, including psychotherapy, chronotherapeutic, and lifestyle modifications, play an essential complementary role. Future directions emphasize personalized medicine, with a focus on clinical phenotyping, biomarker development, and novel therapeutic targets to optimize treatment outcomes in bipolar depression.