Prepulse inhibition of the startle response in men with schizophrenia - Effects of age of onset of illness, symptoms, and medication

Background: Prepulse inhibition of the startle reflex response refers to th e ability of a weak prestimulus to transiently inhibit the response to a cl osely following strong sensory stimulus. This effect represents an operatio nal index of sensorimotor gating and is found to be deficient in schizophre nia. Prepulse inhibition deficits in schizophrenia seem to be partially nor malized by typical antipsychotics and more fully by some atypical antipsych otics. Early onset of schizophrenia, particularly in men, has been associat ed with abnormal brain maturation, profound neuropsychological. deficits, a nd less responsiveness to antipsychotic medication. We evaluated the effect s of the age of onset of illness, current positive and negative symptoms, a nd the type of medication (typical vs atypical) on prepulse inhibition of t he startle response in schizophrenia. Methods: Thirty-eight male schizophrenic patients and 20 healthy male contr ols underwent testing for prepulse inhibition of the acoustic startle respo nse. Results: Earlier onset of illness was associated with reduced prepulse inhi bition, while adult onset of illness was not. No significant relationships occurred between current symptoms and prepulse inhibition. Patients given t ypical, but not atypical, antipsychotics exhibited less prepulse inhibition compared with healthy controls. Conclusion: Early onset of illness is associated with profound deficits in prepulse inhibition of the startle response in men with schizophrenia.