The influence of depressive and manic symptoms on suicidal ideation in mixed mood states.

Background: While bipolar disorder is strongly linked to an increased risk of suicide, recent evidence has challenged the assumption that mixed symptoms play a distinct role in suicidal ideation beyond depressive severity. This study examines how depressive, hypo/manic, and mixed features influence suicidal ideation in individuals with bipolar disorder. Data from 903 participants in the Stanley Foundation Bipolar Network (1995-2002) were analyzed to assess associations between mood states, classified by the Inventory of Depressive Symptomatology-Clinician-Rated (IDS-C) and the Young Mania Rating Scale (YMRS), and suicidal ideation, measured using IDS-C item 18, using generalized estimating equations.

Results: Depressive symptoms were strongly associated with suicidal ideation (OR = 21.98, 95% CI: 15.31-31.54). Moderate hypo/manic symptoms also conferred risk (OR = 3.11, 95% CI: 1.51-6.49), and milder hypo/mania showed a weaker but significant association (OR = 1.74, 95% CI: 1.05-2.89). The highest suicidal ideation was observed in individuals with hypo/mania featuring mixed symptoms (OR = 29.43), exceeding that of depression or depression with mixed features (OR = 21.98). However, findings diverged based on modeling approach: in continuous predictor models, SI was driven solely by depressive symptom severity, with no significant association observed for hypo/mania or its interaction with depression. In contrast, when mood states were categorized using clinically meaningful thresholds, hypo/mania with mixed features emerged as a distinct contributor to suicidal ideation risk.

Conclusion: These findings underscore the need for integrating both dimensional and categorical approaches to mood state classification in research on suicidality in bipolar disorder.