Bimonthly mood-suicidal ideation dynamics in bipolar spectrum disorders: A dynamic structural equation modeling study

Individuals with bipolar spectrum disorders (BSDs) experience a high burden of suicidal ideation (SI). Mania and depression are established correlates of suicidal ideation in BSDs, and externalizing traits (aggression, hostility, and impulsivity) are elevated in BSDs and linked to suicidal thinking and behavior more broadly. We tested temporal within-person mood-SI coupling and whether externalizing traits moderate these dynamics.

Participants were 434 adults with BSDs from the Prechter Longitudinal Study who completed bimonthly assessments over multiple years. Dynamic structural equation modeling (DSEM) was used to characterize within-person dynamics of mania, depression, and SI and to test moderation by trait aggression, hostility, and impulsivity.

Results indicated substantial autoregressive carryover and within-person variability in SI, mania, and depression. Within-person increases in mania predicted higher SI, whereas SI did not significantly predict mania. In contrast, depression and SI were bidirectionally coupled, with increases in either predicting higher levels of the other at the next assessment. Higher aggression, hostility, and impulsivity were associated with greater mean symptom burden, stronger SI carryover, and greater SI variability. Hostility modestly moderated the mania-to-SI path in unadjusted models, but this effect was no longer significant after adjusting for age and gender, while other key lagged effects remained significant.

These results suggest that mania and depression show distinct temporal links with SI and that externalizing traits are associated with greater SI burden and instability. Taken together, our findings support the future development of idiographic, trajectory-informed monitoring approaches in BSDs, pending prospective validation of their clinical utility.