Suicidal Behavior among Forensic Patients in Japan: Risk Factors and Implications for Treatment

Purpose In Japan, the Medical Treatment and Supervision Act (MTSA) was enacted in 2005 to provide intensive interventions for forensic patients. Despite this, these individuals face considerable challenges with social reintegration and exhibit a higher suicide risk. Consequently, identifying risk factors for suicide among forensic patients is crucial. Despite the clear need, few studies have examined these risk factors in Japan. Methods We compiled a near-comprehensive database covering 12 years of data on Japanese forensic outpatients. Using a generalized linear model (GLM), we investigated the relationship between suicidal behavior—including both attempted and completed suicides—and several variables. These variables included the outpatient pathway as defined by the law, psychiatric outpatient/inpatient treatment history, diagnoses of schizophrenia or mood disorder, type of crime committed, and type of victim involved. Results Our analysis included data from 2,263 Japanese forensic outpatients. We observed suicidal behaviors in 6.9% of these patients, with 1.5% completing suicide. Risk factors for suicidal behavior included being a direct outpatient (odds ratio [OR] = 1.63, 95% confidence interval [CI]: 1.14–2.34), having a history of outpatient treatment (OR = 1.92, 95 %CI: 1.07–3.48), and being arrested for arson (OR = 2.24, 95% CI: 1.33–3.76). Conversely, a diagnosis of schizophrenia was linked to a decreased risk of suicidal behavior (OR = 0.61, 95% CI: 0.39–0.95). Conclusion Given that forensic patients are at a higher risk of suicide compared to the general population, it is imperative to consider risk and protective factors when intervening with these individuals.