Predicting factors for non-suicidal self-injury in patients with schizophrenia spectrum disorders and the role of substance use.

Non-suicidal self-injury (NSSI) has been shown as a characteristic feature in many clinical populations in recent years and schizophrenia is one of the most common psychiatric disorders which is associated with NSSI. In this study, we aimed to investigate predictors of NSSI in patients with schizophrenia spectrum disorders (SSD) and the role of lifetime substance use disorder (SUD). A sample of 165 patients with a diagnosis of SSD who were in remission participated in the study. Lifetime NSSI was assessed using the Inventory of Statements About Self-injury (ISAS). Lifetime SUD were evaluated. Logistic regression analysis was conducted to predict NSSI. SUD was found to be related to NSSI in patients with SSD, and it was associated with an approximately fourfold increase in the risk of NSSI. The rates of lifetime SUD in our sample and in the NSSI (+) group were 38.2 % and 55.6 %, respectively. The most commonly abused substances among patients with NSSI were cannabis and synthetic cannabinoids. The prevalence of NSSI was 43.6 % in our sample. 'Self-cutting' was the most common type and 'affect regulation' was the most common function of NSSI. One of the most significant risk factors for NSSI was a previous history of suicide attempts. SUD appears to be a significant predictor of NSSI in patients with SSD. Further investigation of treatable risk factors such as SUD which are related to NSSI is needed. It is also essential to screen SSD patients for NSSI due to the probable relation to high risk of suicide.