Neurocognitive vulnerability: suicidal and homicidal behaviours in patients with schizophrenia.
OBJECTIVE
Schizophrenia is associated with an increase in the risk of both homicide and suicide. The objectives of this study were to systematically review all published articles that examined the relation between neurocognitive deficits and suicidal or homicidal behaviours in schizophrenia, and to identify vulnerabilities in suicidal and homicidal behaviour that may share a common pathway in schizophrenia.


METHODS
A systematic review of the literature was performed using MEDLINE to include all studies published up to August 31, 2012.


RESULTS
Among the 1760 studies, 7 neuropsychological and 12 brain imaging studies met the selection criteria and were included in the final analysis. The neuropsychological and functional neuroimaging studies were inconclusive. The structural imaging studies reported various alterations in patients with schizophrenia and a history of homicidal behaviour, including: reduced inferior frontal and temporal cortices, increased mediodorsal white matter, and increased amygdala volumes. Patients with a history of suicidal acts showed volumetric reductions in left orbitofrontal and superior temporal cortices, while right amygdala volume was increased, though, these findings have rarely been replicated. Finally, no study has directly compared neurocognitive markers of suicidal and homicidal risk.


CONCLUSIONS
These results suggest that brain alterations, in addition to those associated with schizophrenia, may predispose some patients to a higher risk of homicide or suicide in particular circumstances. Moreover, some of these alterations may be shared between homicidal and suicidal patients. However, owing to several limitations, including the small number of available studies, no firm conclusions can be drawn and further investigations are necessary.
Psychiatrist, Postdoctoral Fellow in Neuroscience, Department of Psychiatry and Douglas Mental Health University Institute, McGill Group for Suicide Studies, McGill University, Montreal, Quebec; Associate Member, Laboratoire de Psychologie des Pays de la Loire, UPRES EA 4638, Université d'Angers, Angers, France.
Stéphane
S
Richard-Devantoy
Psychiatrist, Secteur 16 de Psychiatrie Adultes, Centre Hospitalier Spécialisé de la Sarthe, Allonnes, France.
Manuel
M
Orsat
Psychiatrist, Assistant Professor, Department of Psychiatry and Research Centre-Pinel Institut, University of Montreal, Montreal, Quebec.
Alexandre
A
Dumais
Professor, Departments of Psychiatry, Human Genetics, and Neurology and Neurosurgery, McGill University, Montreal, Quebec; Vice-Chair, Research and Academic Affairs, Department of Psychiatry, McGill University, Montreal, Quebec; Director, McGill Group for Suicide Studies, Montreal, Quebec; Co-Director, Douglas-Bell Canada Brain Bank (suicide studies), Montreal, Quebec; Head, Depressive Disorders Program, Douglas Institute, Montreal, Quebec; Director, Réseau québécois de recherche sur le suicide, Montreal, Quebec.
Gustavo
G
Turecki
Assistant Professor, Department of Psychiatry and Douglas Mental Health University Institute, McGill Group for Suicide Studies, McGill University, Montreal, Quebec.
Fabrice
F
Jollant
D001921:Brain / Q000503:physiopathology*; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology*; D006708:Homicide / Q000523:psychology*; D006801:Humans; D012559:Schizophrenia / Q000150:complications / Q000503:physiopathology*; D013405:Suicide / Q000523:psychology*
amygdala; executive functions; homicide; schizophrenia; suicide; systematic review