Characteristics and predictive factors of non-suicidal self-injury in patients with schizophrenia spectrum disorders

Objective: This study was designed to evaluate the characteristics and functions of non-suicidal self-injury (NSSI) in patients with schizophrenia spectrum disorders (SSD) and to investigate predictive factors of NSSI. Method: A total of 102 patients aged 18-65 years with a diagnosis of SSD according to DSM-5 criteria, who were in remission were consecutively recruited for the study. Lifetime NSSI was assessed using the Inventory of Statements About Self-injury. The Positive and Negative Syndrome Scale, the Calgary Depression Scale, the Suicide Probability Scale, the Dissociation Questionnaire, the Schedule for Assessing the Three Components of Insight, and the Barratt Impulsivity Scale-11 were administered to all of the participants. Logistic regression analysis was conducted to predict NSSI. Results:The prevalence of NSSI was 31.4% in our sample. Self cutting was the most common type (26.1%), and affect regulation was the most common function of NSSI. Among the NSSI (+) group, 65.6% preferred to be alone when performing self-injurious behavior. The time between the onset of an urge to self-injure and the onset of self-injurious behavior was most often <3 hours (46.9%). Significant predictors of NSSI were a history of a suicide attempt (Odds ratio [OR]: 2.693, p=0.040, 95% confidence interval [CI]: 1.048-6.921) and a greater severity of depressive symptoms (OR: 1.216, p=0.001, 95% CI: 1.081-1.367). A history of a suicide attempt was associated with an approximately threefold increase in the risk of NSSI. The probability of suicide was higher among patients with NSSI than in patients without NSSI. Conclusion: Approximately one-third of the SSD patients in this study reported NSSI. The results indicated that patients with severe depressive symptoms and a history of a suicide attempt were more at risk of injuring themselves and that the probability of suicide was higher in patients with NSSI than in patients without NSSI. A reciprocal relationship between NSSI and suicide underlines the necessity for careful investigation of both clinical situations in this patient group. Assessment of NSSI should be a part of the standard suicide risk assessment of SSD patients. Effective treatment of affective symptoms would likely help to reduce the risk of NSSI.