Suicidal ideation in individuals at ultra-high risk for psychosis and its association with suspiciousness independent of depression

Aim Psychotic experiences, including delusions and hallucinations, and their attenuated forms have been recently suggested as a significant but under-recognized marker of suicide risk. However, the relationship between attenuated positive symptoms and suicide has not yet been clearly demonstrated in individuals at ultra-high risk (UHR) for psychosis. Here, we investigated the effect of attenuated positive symptoms on suicidal ideation in UHR individuals. Methods Fifty-three healthy controls (HCs) and 74 UHR individuals participated in the present study. All participants were assessed for the intensity of suicidal ideation and depressive symptoms at baseline. The effect of attenuated positive symptoms on suicidal ideation in the UHR group was examined using a multiple linear regression analysis after adjustment for concurrent depressive symptoms. Results UHR participants were found to have significantly greater suicidal ideation and more severe depressive symptoms compared to those of HCs. The regression model demonstrated that suspiciousness significantly increased suicidal ideation in UHR participants, independent of the severity of depressive symptoms. Conclusion The findings of the present study suggest that suspiciousness may serve as a risk indicator for suicide in clinical practice for UHR individuals. It is crucial to focus on the risk of suicide in the UHR population, as they require sufficient clinical attention and proper management for crises related to their unusual and confusing experiences.