This study has used neuropsychological tasks - Wisconsin Card Sort (WC
ST), Trail Making (TMT) A and B, Verbal Fluency, Digit Span - to compa
re acute and currently off-medication schizophrenics, patients with un
ipolar nonpsychotic major depression and healthy controls. Both patien
t groups differed significantly from healthy controls in their neurops
ychological performance. Furthermore there was only little (quantitati
ve) difference between schizophrenics and depressed patients in the fr
ontal lobe associated tasks: WCST. TMT and Verbal Fluency. Depressed p
atients tended to perform worse than schizophrenics on Digit Span, a t
ask hypothesized to involve other than frontal areas of the brain. Alt
hough the group of depressed patients was older than the schizophrenic
sample, the effect of age may not totally explain the findings. The r
esults indicate that there do exist disturbances in frontal lobe cogni
tive functioning in schizophrenia and depression. Symptomatology (SANS
/SAPS) and cognitive functioning in the schizophrenic group revealed o
nly a trend for negative symptoms to be associated with worse performa
nce in the WCST, but were significantly correlated with negative as we
ll as positive symptoms on the TMT.