Suicidality clues reside in gray matter
medwireNews: Patients with psychotic disorders who attempt suicide have marked structural changes in their gray matter relative to those who do not show suicidal behavior, shows an analysis of the Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP) cohort.
“If the observed alterations in specific brain regions are replicated, they could be of corroborative value for clinicians while assessing suicide risk of the patient,” say study author Matcheri Keshavan (Harvard Medical School, Boston, Massachusetts, USA) and team.
However, they stress that their study cannot establish causality. “Brain structural alterations probably account for only a small part of the variation underlying suicidal behavior,” they write in the Journal of Psychiatric Research. “There are many risk factors underlying suicidal behavior in patients with psychosis.”
Among 489 patients with a psychosis spectrum diagnosis, the 148 who had attempted suicide had significantly smaller gray matter volumes than other patients in the bilateral inferior temporal and superior temporal regions, the right insula, superior frontal and rostral middle frontal regions, and the left superior parietal and supramarginal regions.
Both groups of patients had significantly smaller gray matter volumes in these areas relative to 262 mentally healthy controls.
To account for the possibility of suicide attempts themselves being responsible for gray matter changes, the team divided attempters into 97 with a high-lethality attempt – defined as a score of at least 2 on the Lethality Scale, indicating that the attempt caused significant medical issues – and 51 with a low-lethality attempt.
The high-lethality group had significant gray matter reductions in the left lingual area and right cuneus, relative to the low-lethality group, but the latter group had significant reductions in the left supramarginal area, left thalamus, and right insula, relative to patients who did not attempt suicide.
The researchers therefore suggest that the identified structural changes are “a sensitive marker of suicidal behavior.”
Keshavan et al also note that the associations make sense in that the affected areas control functions that could contribute to suicidal behavior.
For example, “the rostral middle frontal gyrus is part of the prefrontal cortex which is implicated in cognitive analysis, foresight and weighing possible consequences of behavior, considering the future and making predictions, impulse control and delaying gratification, inhibiting inappropriate behavior and initiating appropriate behavior,” they explain.
This is consistent with the previously reported link between impulsivity and suicide risk in schizophrenia patients, they add.
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Eleanor McDermid, Senior medwireNews Reporter