Suicide attempts, white matter microstructure, and cognitive function in schizophrenia

White matter abnormalities are important for understanding schizophrenia and related behaviors. However, the relationship between a history of suicide attempts and alterations in white matter microstructure among individuals with schizophrenia, and its impact on neurocognition, remains unclear.

This study scanned 283 individuals diagnosed with schizophrenia and 189 healthy controls. Fractional anisotropy (FA) derived from diffusion tensor imaging is used to assess white matter microstructure. Neurocognitive performance was assessed using the MATRICS Consensus Cognitive Battery.

Compared to healthy controls, schizophrenia patients with a history of suicide attempts showed widespread reductions in white matter FA across multiple brain regions (FDR-corrected p < 0.05). In uncorrected analyses, patients with a history of suicide attempts showed a significant lower FA in the external capsule (EC) (p = 0.033, Cohen's d = -0.26) compared to patients without such history; two-week suicidal ideation was also associated with lower FA in the inferior fronto-occipital fasciculus (p = 0.018, d = -0.29). After FDR correction, none remained significant (all adjusted p > 0.05). A significant interaction was observed between suicide‑attempt history and EC FA in relation to the social cognition T‑score (p for interaction = 0.022).

Contrary to prior findings in mood disorders, we did not observe robust white matter microstructural alterations associated with suicide attempts in schizophrenia. EC FA was significantly associated with social cognition performance only in patients without a history of suicide attempts.