Problem-solving abilities in unipolar depressed patients: comparison of performance on the modified version of the Wisconsin and the California sorting tests

Problem solving relies on such abilities as decision-making, planning, init iation and hypothesis testing. Although problem-solving deficits have been consistently reported in depression, the specific nature of these deficits is not fully elucidated. In order to assess and isolate cognitive processes underlying problem-solving impairments in depression, depressed patients a nd normal controls were evaluated with the modified version of the Wisconsi n Card Sorting Test (WCST) and the California Card Sorting Test (CCST). The California Card Sorting Test, unlike the modified WCST, provides several d ifferent measures of concept generation, concept identification and concept execution. Compared with controls, depressed patients did not show any def icits on all the measures of the modified WCST. In contrast, depressed pati ents evidenced mild impairment on the CCST with a specific deficit on conce pt generation but no major problems in concept identification and concept e xecution. The deficit in concept generation may be rooted in multiple facto rs such as hypothesis-testing deficits, a loss of cognitive flexibility and a conservative style of response. Since a positive relation between proble m-solving deficits and the mean duration of the depressive episode was obse rved, problem-solving abilities might be predictive of poorer outcome in pa tients with unipolar affective disorders. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.