The neuropsychological basis of first-rank symptoms in schizophrenia (FRS) is still a matter of debate. Three broad explanatory models for FRS have been proposed, each arising from a different perspective: (i) medial temporal lobes pathology (Trimble, 1990); (ii) reduced cerebral lateralisation and interhemispheric transfer (Crow, 1997); and (iii) deficits in self-monitoring of intentions due to prefrontal inhibitory dysfunction (Frith et al, 2000). The aim of the study was to test whether patients with FRS would show deficits consistent with the above models.

A broad range of neuropsychological tests were administered to patients with and without FRS and to healthy controls, comprising tests of verbal and nonverbal memory, measures of cerebral lateralisation and interhemispheric communication, tasks of executive functioning, as well as tests of general cognitive abilities.

On some cognitive tests, results were supportive of theories advocating reduced cerebral lateralisation and self-monitoring impairment. An unexpected finding was that, on many cognitive tasks, the performance of patients with FRS was better than that of patients without FRS, and not significantly different from that of controls. These results could not be accounted for by demographic features or medication effects.

The current study may be the most comprehensive examination of neuropsychological performance in patients with FRS to date. Our results suggest that broad cognitive impairment is not a necessary correlate of FRS.