Impaired Executive Function Linked to Suicidal Behavior in Elderly

More than other dimensions of cognition, executive function appears to be a key indicator of long-term outcomes in elderly patients. Impaired executive function has been linked to greater suicide risk in patients with depression, as well as worsening behavior disturbance in dementia patients, according to two studies in the February American Journal of Geriatric Psychiatry.

In a case-control study conducted by Alexandre Dombrovski, M.D., and colleagues, 32 people aged 60 or older who had severe suicidal ideation (with a specific plan, causing them to be hospitalized) or who had made suicide attempts within the previous three months, were compared with 32 elderly participants with matching demographics but who were not suicidal.

Both groups met DSM-IV criteria for depression and had similar scores on the Mini-Mental State Examination. But the suicidal participants had significantly worse executive function than nonsuicidal ones in the Executive Interview (EXIT25), a 25-item test that detects left frontal cortical pathology. This difference in executive function persisted after the authors controlled for dementia, substance use, medications, or brain injury due to suicide attempts.

The suicidal participants were also significantly worse in global cognitive function, measured by the Dementia Rating Scale and in its attention and memory subscale, but not in initiation, construction, or the conceptualization subscales. The study was funded by grants from the National Institutes of Health, University of Pittsburgh Medical Center, and John A. Hartford Foundation.

Executive-function impairment in early stages of dementia was also found to predict more severe behavior disturbance in patients with dementia, another study reported. Researchers at Leicester General Hospital in the United Kingdom followed a group of elderly patients with mild to moderate dementia.

In the 42 dementia patients for whom data were available, higher scores for executive function on the Cambridge Examination for Mental Disorders of the Elderly-Revised were statistically significantly associated with greater behavior disturbance and caregiver distress three to six years later. Global cognitive impairment at baseline, however, was not significantly predictive.

While neither study was randomized or had a large sample size, both add to the growing neuropsychiatry research into the role of prefrontal cortex in certain dimensions and outcomes of mental illness.

“Clearly evident in all of these articles is the substantial importance of cognitive impairments in later life adjustment,...[and] not all cognitive impairments are the same,” wrote Philip Harvey, Ph.D., a professor of psychiatry at Emory University School of Medicine, in an accompanying editorial in the journal.

Harvey and both studies' authors acknowledged that medical science still has little knowledge about why and how executive-function impairment is so detrimental to outcomes in not only the elderly, but also in younger patients with mental illness. And even less is known, they said, about whether anything can be done to prevent or mitigate the impairment. They recommended the use of more comprehensive cognitive assessment, especially of executive function, in elderly patients with a variety of conditions.

An abstract of “Cognitive Performance in Suicidal Depressed Elderly: Preliminary Report” is posted at<ajgponline.org/cgi/content/abstract/16/2/109>. An abstract of “Early Frontal Executive Impairment as a Predictor of Subsequent Behavior Disturbance in Dementia” is posted at<ajgponline.org/cgi/content/abstract/16/2/102>.▪