Background: Suicidal behavior results from a complex interplay between stressful events and vulnerability factors, including cognitive deficits. However, it is not clear which cognitive tests may best reveal this vulnerability. The objective was to identify neuropsychological tests of vulnerability to suicidal acts in patients with mood disorders.
Method: A search was made of Medline, EMBASE and PsycINFO databases, and article references. A total of 25 studies (2323 participants) met the selection criteria. A total of seven neuropsychological tests [Iowa gambling task (IGT), Stroop test, trail making test part B, Wisconsin card sorting test, category and semantic verbal fluencies, and continuous performance test] were used in at least three studies to be analysed.
Results: IGT and category verbal fluency performances were lower in suicide attempters than in patient controls [respectively, g = -0.47, 95% confidence interval (CI) -0.65 to -0.29 and g = -0.32, 95% CI -0.60 to -0.04] and healthy controls, with no difference between the last two groups. Stroop performance was lower in suicide attempters than in patient controls (g = 0.37, 95% CI 0.10-0.63) and healthy controls, with patient controls scoring lower than healthy controls. The four other tests were altered in both patient groups versus healthy controls but did not differ between patient groups.
Conclusions: Deficits in decision-making, category verbal fluency and the Stroop interference test were associated with histories of suicidal behavior in patients with mood disorders. Altered value-based and cognitive control processes may be important factors of suicidal vulnerability. These tests may also have the potential of guiding therapeutic interventions and becoming part of future systematic assessment of suicide risk.