The neuropsychology of suicidal states in depressed inpatients

Abstract

Suicide has been a considerable public health issue for many years and a greater understanding of it is critical for prevention. Depression, the diagnosis most commonly associated with suicidal behavior, has been related to frontal lobe dysfunction. Suicidal thinking may be a maladaptive "executive" decision made by someone who exhibits cognitive rigidity and dichotomous thinking (i.e. a person who fails to see solutions to problems other than suicide). As the "executive" decision center of the brain, the frontal lobe may be dysfunctional in suicidal persons.;The aim of this study was to test the hypothesis that depressed, suicidal subjects would perform worse than depressed nonsuicidal subjects on measures of executive frontal lobe function. The study involved two groups of psychiatric inpatients with diagnoses of unipolar or bipolar depression, 28 who were actively suicidal and 25 who were not actively suicidal. Both groups were administered a series of neuropsychological measures assessing frontal lobe functioning. In addition, both groups received the Boston Naming Test and the Rey copy condition which are not primarily measures of frontal lobe function to determine if diminished neuropsychological performance was primarily frontal or involved all areas of the brain (i.e. diffuse). The two study groups were similar in gender, education, estimated verbal IQ, diagnosis and illness characteristics, severity of depression, anxiety and impulsiveness, and their use of psychotropic medications. Minor differences in age were noted.;Compared to nonsuicidal depressed inpatients, the suicidal inpatients demonstrated significantly worse performance on the Wisconsin Card Sorting Test, Trail Making Test (B minus A), verbal fluency, Stroop interference and WISC-III Mazes. No group differences were noted on nonverbal fluency and WCST categories completed and failure to maintain set. As hypothesized, no significant group differences were noted on the Boston Naming Test and the Rey copy condition.;These findings indicate that the suicidal mental states among depressed inpatients are associated with frontal lobe dysfunction above and beyond that seen in depression. Understanding frontal lobe dysfunction in depressed patients may prove helpful in the prediction, treatment and prevention of suicide.