Atypical antipsychotics do not reverse prepulse inhibition deficits in acutely psychotic schizophrenia

To investigate the effects of atypical antipsychotics on prepulse inhibition, startle response and habituation in acutely psychotic patients with schizophrenia, and investigate whether prepulse inhibition deficit improvements are a result of the direct impact of atypical antipsychotics or improvements in antipsychotic-related symptoms.

Prepulse inhibition, habituation and acoustic startle response were evaluated in healthy control subjects and patients with schizophrenia (either unmedicated with antipsychotics at the time of hospitalization or medicated with atypical antipsychotics for ≥1 month before hospitalization).

Data were analysed for 26 patients in the unmedicated group, 20 patients in the medicated group and 31 control subjects. Compared with controls, both medicated and unmedicated patients showed prepulse inhibition deficits; however, there were no significant differences between the two patient groups. Lower prepulse inhibition levels were correlated with higher levels of positive, negative, general and total scores on the Positive and Negative Syndrome Scale.

These results suggest that effects of atypical antipsychotics on prepulse inhibition may not be evident when patients with schizophrenia are acutely symptomatic, and do not directly influence prepulse inhibition.