The influence of schizotypy traits on prepulse inhibition in young healthy controls

Deficits in sensorimotor gating or prepulse inhibition (PPI) have been demonstrated repeatedly in patients with schizophrenia or with schizotypal personality disorder, but not consistently in schizotypal non-psychiatric controls. The appearance of normal PPI in this group has been interpreted as reflecting a discontinuous underlying vulnerability to psychosis in high-risk groups. An alternative interpretation is that underlying vulnerability to psychosis is continuously distributed in the normal population (Claridge, 1972, 1987), and therefore that performance on information processing tasks should vary continuously with increasing levels of schizotypy in non-clinical populations. We attempted to examine further the notion of a continuous relationship between PPI and schizotypy in 44 (17 female, 27 male) healthy, non-smoking subjects controlling for menstrual phase. In this selected sample, the findings do not support a continuum model, and suggest that PPI deficits may indeed be the result of a discontinuous neurophysiological change in those with psychotic illness, rather than one continuously distributed in the normal population.