Attentional effects on prepulse inhibition of the acoustic startle reflex in patients with schizophrenia

Funded Activity Summary

People suffering from schizophrenia exhibit differences from healthy people in the startle reflex, which is a blink of the eyes when a sudden loud sound occurs. Normally, this reflex is reduced in size when a quiet sound occurs a few milliseconds before the startling sound, but this prepulse inhibition of the startle reflex or PPI does not occur to the same degree in people with schizophrenia. The underlying causes of this reduction in PPI in patients with schizophrenia is not known. The most commonly accepted theory is that it reflects a deficit in a basic sensorimotor gating function which could underlie a variety of attentional abnormalities observed in schizophrenia. However, our data indicate that patients exhibit more PPI when they ignore the prepulse stimuli. We wish to test the hypothesis that alterations in PPI in schizophrenic patients are secondary to abnormalities in attention. This is significant because the theory can point to a specific cognitive deficit associated with schizophrenia. We have also found that patients treated with some kinds of antipsychotic medications (the newer atypical antipsychotic medications) do not show reductions in PPI, but patients treated with older types of antipsychotic drug do show reductions in PPI. We intend to investigate the effects of different types of antipsychotics on attentional modulation of PPI. This is significant because it may indicate that patients with a specific kind of cognitive impairment may show improvement with a specific type of medicine. Our data suggests that chronic cannabis use may associated with differences in the startle reflex and in PPI. Understanding how such cannabis use alters PPI may provide insights into why so many people with schizophrenia regularly abuse cannabis.

Funded Activity Details

Start Date: 01-01-2003

End Date: 01-01-2005

Funding Scheme: NHMRC Project Grants

Funding Amount: $278,625.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Psychiatry

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

attention | atypical antipsychotics | biological correlates of schizophrenia | cannabis | comorbidity of substance abuse with schizophrenia | differential medication effects in schizophrenia | neuroleptics | prepulse inhibition of startle reflex | schizophrenia | substance abuse

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