Cognitive function not linked to suicidality in schizophrenia
MedWire News: Results from a Norwegian study suggest that neurocognitive functioning is not associated with suicidal behavior in patients with schizophrenia spectrum disorders.
Previous research has shown that schizophrenia patients are at increased risk for suicide. They have also been shown to have significant neurocognitive impairment in a variety of neurocognitive domains, including memory, working memory, vigilance, and executive functioning, which contribute to difficulties in performing daily activities.
However, Elizabeth Barrett (Oslo University Hospital) and team explain that few studies have examined the association between neurocognitive domains and suicidal behavior in schizophrenia patients.
The researchers therefore studied 174 patients with schizophrenia spectrum disorders who were aged between 18 and 65 years.
All of the participants were assessed using the Positive and Negative Syndrome Scale, and underwent the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I), which includes questions on suicide attempts.
The participants' IQ and neurocognitive functioning were assessed using an extensive test battery, which included the National Adult Reading Test, the Wechsler's Abbreviated Scale of Intelligence, the Color-Word Interference Test and the Verbal Fluency Test from the Delis Kaplan Executive Functioning Scale, the Grooved Pegboard test, and the California Verbal Learning Test.
In total, 53 patients reported a history of suicide attempts. Of these, 29 had made a single suicide attempt and 24 had made multiple attempts.
The researchers found that there were significant differences between patients who had and had not attempted suicide regarding mean age at illness onset (21 vs 23 years), duration of illness (9.1 vs 6.1 years), and depressive episodes (1 vs 0 episodes). Patients who had attempted suicide also had less insight and were more likely to have used sedatives than those who had not.
However, there were no significant differences between suicide attempters and non-attempters regarding IQ measures or performance on any of the neurocognitive tests.
There were also no significant differences in neurocognitive performance between patients who had attempted suicide just once and those who had made multiple attempts.
Barrett and team comment in the journal Comprehensive Psychiatry: "Contrary to our expectations, we found that suicide attempters neither had significantly higher IQ, better executive functioning, nor higher impulsivity (poorer inhibitory control) than non-attempters. Furthermore, the groups did not differ in motor functioning, psychomotor tempo, attention, or memory."
They conclude: "These findings indicate that neurocognitive traits are not an essential part of a predisposition for suicidal acts in patients with schizophrenia spectrum disorders."
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By Mark Cowen