Overview of forensic outpatients on the Medical Treatment and Supervision Act in Japan

Int J Law Psychiatry. 2025 May-Jun:100:102074. doi: 10.1016/j.ijlp.2025.102074. Epub 2025 Feb 18.

Abstract

In Japan, the Medical Treatment and Supervision Act (MTSA) has been in effect since 2005, and a support system has been established for those found not guilty by reason of insanity (NGRIs). Under this law, the reintegration of the subjects into society is underway. This paper summarizes the status of forensic outpatients during the seven years after its enactment. Information on forensic outpatients was obtained from 224 designated outpatient medical institutions under the law between 2005 and 2011, the period after the law's implementation. Information on demographic factors, psychiatric status, forensic background, clinical treatment history, and social service utilization was collected. Among the 690 outpatients, the most common diagnosis was F2 (Schizophrenia) (76.4 %), and the most common criminal offense was homicide/attempted homicide (28.8 %). Among the outpatients, 46.2 % developed problematic behavior during treatment, and suicidal behavior was observed in 6.0 % of the patients. Since problematic behaviors during treatment, including suicidal behavior, have been observed, it is necessary to expand support, including the development of proper relationships with patients and the early stages of treatment to promote the integration of forensic patients into society.

Keywords: Crime; Forensic patient; Insanity; Medical Treatment and Supervision Act (MTSA); Outpatient treatment; Problematic behavior.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Female
  • Forensic Psychiatry
  • Homicide / statistics & numerical data
  • Humans
  • Insanity Defense*
  • Japan / epidemiology
  • Male
  • Mental Disorders* / epidemiology
  • Mental Disorders* / psychology
  • Mental Disorders* / therapy
  • Middle Aged
  • Outpatients* / legislation & jurisprudence
  • Outpatients* / psychology
  • Outpatients* / statistics & numerical data
  • Young Adult