Forensic mental health services exist in a nebulous space at the intersection of two different systems―criminal justice and mental health―and the entanglement of these systems poses intricate problems for psychiatrists. This article discusses the present circumstances of forensic mental health services in Japan, focusing on trends in prison psychiatry.
 In the traditional Japanese system, offenders with mental disorders were treated within general psychiatry as involuntarily admitted patients,or within the prison system as mentally ill inmates. As a consequence of recent legal reform, however, this situation has radically changed. The Medical Treatment and Supervision Act of 2005 aimed to provide intensive psychiatric treatment to offenders with mental disorders,attaching great importance to their reintegration into society. Under the new system, a person who commits a serious criminal offense in a state of insanity or diminished capacity shall be referred by the public prosecutor to the district court ; following a treatment order of the court,the person shall be treated in psychiatric facilities established by the law.
 While the new system is expected to play a role in the context of specialist forensic psychiatry, its distinction from general psychiatry remains unclear. For example, persons who commit serious crimes, such as assault, in an acute psychotic state are occasionally admitted to general psychiatric hospitals,even if they meet the criteria for a treatment order under the Medical Treatment and Supervision Act.
 The relationship between prison psychiatry and specialist forensic psychiatry is still more problematic. Compared to the intensive, rehabilitation-oriented care provided under the Medical Treatment and Supervision Act,mental health services in penal institutions have a number of disadvantages, and it is unlikely that mentally ill prisoners have benefited from the recent progress in forensic psychiatry.
 Statistics show that the number of sentenced prisoners with mental disorders has steadily increased during the last decade. Although a majority of these individuals are substance abusers, the number of patients with schizophrenia who are unable to serve a sentence due to severe illness is not insignificant. Although patients are sometimes transferred to medical prisons, a substantial number of inmates with mental disorders remain in general prisons, most of which lack adequate medical staff. Accordingly,the growing number of mentally ill inmates is imposing a heavy burden on the penal administration system.
 Provisions of the Mental Health and Welfare Act pertaining to general psychiatry are not applicable to patients in penal institutions. The Psychiatric Review Board established in each prefecture does not intervene in the management of these facilities. As a result, legal safeguards against the violation of patients’rights are not sufficiently guaranteed in penal institutions.
 There are no legal provisions for transferring patients with severe mental disorders from prisons to psychiatric hospitals. Once sentenced to imprisonment, offenders with mental disorders are treated almost exclusively within the prison system. This situation is particularly serious in the case of patients with long-term sentences. In addition, the continued availability of psychiatric care after discharge from prison, which is crucial for preventing relapse of illness and recidivism,is not assured. When a mentally ill inmate is discharged,the head of the institution is required to report the discharge to the prefectural governor, in accordance with the Mental Health and Welfare Act. Recently,although the number of such reports has sharply increased, in actuality many of the persons reported are not admitted to hospitals because they do not meet the criteria for involuntary admission,and the provisions of the Medical Treatment and Supervision Act do not apply to them.
 In conclusion, more attention should be paid to the reform of prison psychiatry. Coordination of the separate functions of general psychiatry, specialist forensic psychiatry, and prison psychiatry is also important.