NEUROPSYCHOLOGICAL IMPAIRMENTS IN UNIPOLAR DEPRESSION - THE INFLUENCEOF PERCEIVED FAILURE ON SUBSEQUENT PERFORMANCE

The CANTAB battery of neuropsychological tests was used to compare the performance of 28 patients with unipolar depression with that of 22 a ge and IQ matched controls. The patients were impaired on almost all t ests studied with deficits in pattern and spatial recognition memory, matching to sample, spatial span, spatial working memory and planning. Most of the patients showed at least some impairment and deficits wer e seen across cognitive domains. An important finding was the detrimen tal effect of failure on subsequent performance; having solved one pro blem incorrectly, patients were far more likely than controls to fail the subsequent problem. Superimposed on the general deficits, there we re also specific deficits in executive tasks characteristic of frontos triatal dysfunction and deficits in mnemonic tasks characteristic of t emporal lobe dysfunction. This combination of a specific form of motiv ational deficit, resulting in oversensitivity to negative feedback, an d superimposed specific neuropsychological deficits were correlated wi th severity of depression. The most significant correlations were seen between mnemonic deficits and clinical rating scores. Comparisons of the deficits seen in the depressed patients in this study with other p atient groups assessed with the CANTAB neuropsychological battery, sho wed that one of the hypotheses of the neuropsychological deficits in d epression, that of 'frontosubcortical' or 'frontostriatal' dysfunction , was not supported. These findings are discussed in relation to the l ikely neural substrates of depression.