Friday, January 29, 2016

Neuropsychological Impairment and Its Association with Violence Risk in Japanese Forensic Psychiatric Patients

In Japan, the legislation directing treatment of offenders with psychiatric disorders was enacted in 2005. Neuropsychological impairment is highly related to functional outcomes in patients with psychiatric disorders, and several studies have suggested an association between neuropsychological impairment and violent behaviors. However, there have been no studies of neuropsychological impairment in forensic patients covered by the Japanese legislation. This study is designed to examine the neuropsychological characteristics of forensic patients in comparison to healthy controls and to assess the relationship between neuropsychological impairment and violence risk.

Seventy-one forensic patients with psychiatric disorders and 54 healthy controls (matched by age, gender, and education) were enrolled. The CogState Battery (CSB) consisting of eight cognitive domains, the Iowa Gambling Task (IGT) to test emotion-based decision making, and psychological measures of violence risk including psychopathy were used.

Forensic patients exhibited poorer performances on all CSB subtests and the IGT than controls. For each group, partial correlational analyses indicated that poor IGT performance was related to psychopathy, especially antisocial behavior. In forensic patients, the CSB composite score was associated with risk factors for future violent behavior, including stress and noncompliance with remediation attempts.

Forensic patients with psychiatric disorders exhibit a wide range of neuropsychological impairments, and these findings suggest that neuropsychological impairment may increase the risk of violent behavior. Therefore, the treatment of neuropsychological impairment in forensic patients with psychiatric disorders is necessary to improve functional outcomes as well as to prevent violence.

Below:  Magnitude of impairment in forensic patients relative to healthy controls on each CSB measure

Below:  The IGT net scores for the 5 blocks for forensic patients and healthy controls

Full article at:

Hirofumi Nishinaka, Kenji Hashimoto
Division of Clinical Neuroscience, Center for Forensic Mental Health, Chiba University, Chiba, Japan

Jun Nakane
National Hospital Organization Shimofusa Psychiatric Medical Center, Chiba, Japan

Takako Nagata, Mayu Omori, Naotsugu Hirabayashi
Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan

Atsushi Imai, Noriomi Kuroki, Noriko Sakikawa, Osamu Kuroda
Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan

Yoshito Igarashi
Division of Law and Psychiatry, Center for Forensic Mental Health, Chiba University, Chiba, Japan

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