Background: Increasing evidence points at a causal role of neuropsychological dysfunctions in the vulnerability to suicidal behaviour.More specifically, deficits in attention, fluency, decision making, problem solving and mental flexibility have been identified in a number of studies of suicide attempters.More recently, the focus of attention has shifted towards the potential involvement of disturbed processes of decision-making.The current study aimed at investigating the association between attempted suicide and decision making with an emphasis on reward prediction.A number of additional neuropsychological tests were studied in order to investigate their relationship with the reward prediction task.Methods: The study population consisted of formerly depressed suicide attempters, formerly depressed non-attempters and healthy subjects.Current depression and use of psychotropic medication (not SSRIs) were exclusion criteria.Clinical characteristics were assessed using questionnaires, including the Beck Depression Inventory and Becks Hopelessness Scale, the Barrat impulsiveness scale, and the BIS-BAS reward questionnaire.Neuropsychological characteristics were measured using five widely used and validated diagnostic tests, i.e.the Wisconsin Card Sorting Test, the Trail Making Test, the Stroop Task, the Controlled Oral Word Association Test, and the Tower of London task.Additionally, the experimental task, previously used in normal subjects, was adapted to the current clinical population, enabling to assess decision-making and reward prediction.Results: The study showed significant differences in performance on the Tower of London task, the Wisconsin Card Sorting Test and the experimental task, indicating deficiencies in problem solving, mental flexibility and decision-making in suicide attempters.Clinical characteristics did not differ significantly between groups.Conclusion: In general, the results from this study provide additional support for a role of neuropsychological dysfunctioning in the vulnerability to suicidal behaviour.More particularly, this study adds to our current knowledge by demonstrating the involvement of disturbed reward prediction.