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International Journal of Forensic Science & Pathology (IJFP)    IJFP-2332-287X-01-001e

Research Questions Regarding Mental Disorders and Violence

Akihiro Shiina1*

1* Chiba University Hospital, Department of Psychiatry, Chiba, Japan.

*Corresponding Author

Akihiro Shiina,
Chiba University Hospital,
Department of Psychiatry,
Chiba, Japan.

Article Type: Editorial
Received: August 08, 2013; Published: August 26, 2013

Citation: Shiina A (2013) Research Questions Regarding Mental Disorders and Violence. Int J Forensic Sci Pathol. 1(1e), 1-2. doi:

Copyright: Shiina A© 2013. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

One of the tasks for forensic psychiatrists is to clear up the relationship between violent crimes and mental disorders. The defendant cannot be blamed in cases where delusions have influenced his/her behavior decisively. In such cases, the defendant’s criminal responsibility should be carefully evaluated according to the psychiatric evidence. It is possible for the defendant with untreated schizophrenia or some other severe mental disorder to avoid harsh punishments because of their disability [1]. Meanwhile, offenders with mental disorders must be offered adequate mental health services. These treatments are important not only for the offender but also for public safety. Therefore, it is essential to accurately assess an offender’s mental status.

The first question is whether individuals with mental disorders commit violent crimes more frequently than healthy people. This issue is a continuing source of controversy. Some evidence has suggested a close relationship between mental disorders and violent behaviors, and many violent behaviors may directly result from psychotic symptoms [2]. Most clinical practitioners consider that some psychiatric symptoms, such as paranoid delusions, indicate a risk for future violence [3]. Among individuals with mental disorders, those with schizophrenia were most strongly associated with personal violence [4]. In addition, it was reported that patients with organized delusions involving personal and accessible targets were more likely to commit lethal violence [5]. A meta-analysis indicated that psychosis increased the risk of violence by 49%–68% [6].

In contrast, some reports deny the relationship between mental disorders and violence. An analysis of homicide offenders found that psychotic symptoms were not associated with the use of excessive violence [7]. In the study by MacArthur, it was shown that individuals discharged from mental hospitals with no history of substance abuse had the same risk of violence as those without the history of either mental disorders or substance abuse [8]. This survey also suggests that delusions did not increase the overall risk of violence [9]. Although these findings have been broadly discussed [10], the results of the study by MacArthur have been used as a standard for risk assessment in patients with mental disorders.

Recent researches have begun to identify core elements associated with psychiatric symptoms linked to violence, rather than directly examine the relationships between violence and mental disorders. Some symptoms or behaviors, such as substance abuse [11] and subsets of delusional beliefs [12], have been implicated as risk factors for violence. However, command hallucinations may not be associated with violence [13]. Furthermore, it is possible that some types of delusions [14] or negative symptoms of schizophrenia [15] Akihiro Shiina, International Journal of Forensic Science & Pathology 2013, 1:101 2 may play a role in inhibiting violent behaviors.

Another current hypothesis states that some mediators, such as anger [12, 16] or impulsiveness [17], drive patients with mental disorders to exhibit violent behaviors. This idea is considerably vital for clinical settings. Recidivism may be prevented by implementing strategies for controlling anger and other maladaptive behaviors [18], even if the individual’s psychiatric symptoms cannot be suppressed.

Above all, further studies are required to investigate the relationship between mental status and the tendency to commit crimes. To produce valuable findings in such studies, we must be cautious of the associated political and scientific issues, both of which include ethical controversies.

Regarding political issues, we must be aware that discussing this issue can lead to adverse effects on society. It could increase discrimination against individuals with mental disorders, and subsequently complicate or prevent their rehabilitation into the society. We acknowledge that this issue is considerably ambivalent. When an individual with a mental disorder commits a sensational crime, such as the cases of Hinckley (US) [19], M’Naghten (UK) [20], or Takuma (Japan) [21], social concerns against individuals with mental disorders are activated. Emotional arguments inevitably arise and lead to societal changes, some of which are undesired. Thus, specialists must be politically neutral and comment according to scientific evidence.

The other challenge is the methodological limitations of studies that investigate crime. To gain a precise evidence about this matter, prospective studies are needed [2]. However, several factors should be addressed. First, human rights of the individuals participating in such studies must be respected, and it can be difficult to gain informed consent from criminals. Second, in forensic mental health studies, it is considerably more difficult to conduct randomized controlled trials than clinical studies. Finally, collaboration across facilities is essential for accurate results without any troubles.


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