Neurocognitive markers of passive suicidal ideation in late-life depression

Objectives: (1) To delineate whether cognitive flexibility and inhibitory ability are neurocognitive markers of passive suicidal ideation (PSI), an early stage of suicide risk in depression and (2) to determine whether PSI is associated with volumetric differences in regions of the prefrontal cortex (PFC) in middle-Aged and older adults with depression. Design: Cross-sectional study. Setting: University medical school. Participants: Forty community-dwelling middle-Aged and older adults with depression from a larger study of depression and anxiety (NIMH R01 MH091342-05 PI: O'Hara). Measurements: Psychiatric measures were assessed for the presence of a DSM-5 depressive disorder and PSI. A neurocognitive battery assessed cognitive flexibility, inhibitory ability, as well as other neurocognitive domains. Results: The PSI group (n = 18) performed significantly worse on cognitive flexibility and inhibitory ability, but not on other neurocognitive tasks, compared to the group without PSI (n = 22). The group with PSI had larger left mid-frontal gyri (MFG) than the no-PSI group. There was no association between cognitive flexibility/inhibitory ability and left MFG volume. Conclusions: Findings implicate a neurocognitive signature of PSI: poorer cognitive flexibility and poor inhibitory ability not better accounted for by other domains of cognitive dysfunction and not associated with volumetric differences in the left MFG. This suggests that there are two specific but independent risk factors of PSI in middle-and older-Aged adults.