Tohen, Mauricio

ABSTRACT Objective Despite the availability of approved treatments, a substantial proportion of patients with bipolar disorder experience treatment‐resistant bipolar depression (TRBD), characterized by persistent depressive symptoms unresponsive to standard therapies. However, a universally accepted definition of TRBD is lacking. This consensus document, developed by the International Society for Bipolar Disorders (ISBD) Task Force on TRBD, aims to provide a standardized definition of TRBD to facilitate clinical trials, research, and treatment strategies. Methods The Task Force employed a literature review, clinical trials analysis, and expert consensus meetings to define TRBD. Results TRBD was defined as the failure to achieve a significant and sustained clinical response after at least two approved and adequately dosed pharmacological treatments, administered for a sufficient duration with treatment adherence. For bipolar I (BD‐I) depression, approved treatments included quetiapine (300–600 mg/day for ≥ 8 weeks), lurasidone (20–120 mg/day for ≥ 6 weeks), the combination of olanzapine (6–12 mg/day) and fluoxetine (25–75 mg/day for ≥ 8 weeks), cariprazine (1.5–3 mg/day for ≥ 6 weeks), and lumateperone (42 mg/day for ≥ 6 weeks). For bipolar II (BD‐II) depression, approved treatments included quetiapine (300–600 mg/day for ≥ 8 weeks) and lumateperone (42 mg/day for ≥ 6 weeks). Conclusion This consensus definition aims to provide clarity for clinical trials, improve consistency in research, and guide treatment approaches and inform regulatory pathways. It represents a foundational step in addressing the unmet needs in TRBD and promoting the development of innovative therapeutic strategies. Future efforts will focus on adapting the definition to better align with real‐world clinical challenges and optimize patient care.

IntroductionDepressive episodes are often prevalent among patients with bipolar disorder, but little is known regarding the differential patterns of development over time. We aimed to determine and characterize trajectories of depressive symptoms among adults with bipolar disorder during 6 months of systematic treatment.MethodsThe pragmatic clinical trial, Bipolar Clinical Health Outcomes Initiative in Comparative Effectiveness (CHOICE), randomized 482 outpatients with bipolar disorder to lithium or quetiapine. Depressive symptoms were rated at up to 9 visits using the Montgomery‐Asberg Depression Rating Scale (MADRS). Growth mixture modeling was utilized to identify trajectories and multinomial regression analysis estimated associations with potential predictors.ResultsFour distinct trajectories of depressive symptoms were identified. The responding class (60.3%) with a rapid reduction and subsequent low level; the partial‐responding class (18.4%) with an initial reduction followed by an increase during the remaining weeks; the fluctuating class (11.6%) with a fluctuation in depressive symptoms; and the non‐responding class (9.7%) with sustained moderate‐severe depressive symptoms. Bipolar type I predicted membership of the non‐responding class and randomization to quetiapine predicted membership of either the responding or the non‐responding class.ConclusionApproximately 30% experienced a partial or fluctuating course, and almost 10% had a chronic course with moderate‐severe depression during 6 months. Patients diagnosed with bipolar type 1 had higher risk of being categorized into a class with a worse outcome. While no differences in average overall outcomes occurred between the lithium and quetiapine groups, trajectory analysis revealed that the lithium group had more variable courses.