Depressive symptoms carry an increased risk for suicidal ideation and behavior in bipolar disorder without any additional contribution of mixed symptoms

Objectives: To determine whether the risk of suicidal ideation or behavior during mixed states exceeds that attributable to the depressive components of these states alone in bipolar disorder. Methods: We utilized real-world, longitudinal clinical data collected on 290 patients with bipolar disorders (bipolar I, bipolar II, and bipolar not otherwise specified (NOS)) from the National Network of Depression Centers (NNDC) Clinical Care Registry (CCR) seen for 891 visits over a mean of 27.5 weeks. Depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9), manic symptoms with the Altman Self-Rating Mania (ASRM), and suicidal ideation and behavior with the Columbia-Suicide Severity Rating Scale (C-SSRS), obtained as part of the routine, measurement-based care provided across the NNDC. The relations between depressive symptoms, manic symptoms, and the interaction thereof (mixed symptoms) on coinciding suicidal ideation and behavior were modeled in generalized linear mixed models. Results: Depressive symptoms, as measured by the PHQ-9, were strongly associated with suicidal ideation and behavior (p < 0.0001), while there was no significant association with manic symptoms as measured by the ASRM or the interaction between depressive and manic symptoms. Similar results were observed when the outcome was restricted to suicidal behavior and when mood was modeled categorically. There was evidence of a gender by ASRM interaction (p = 0.011) and risk of suicidal ideation or behavior was significant for women, but not men with manic symptoms. Limitations: Diagnoses were based on clinician assessment and not structured interview. Mood assessments were self-reported rather than clinician-administered. Suicidal ideation was more frequently observed than suicidal behavior (23/272 visits where outcome positive). Conclusions: Depression represents the primary mood state accounting for suicide risk in bipolar disorder. Co-occurring symptoms of mania (mixed symptoms) do not appear to convey an elevated risk for suicidal ideation or behavior beyond that explained by the depressive symptoms alone.