Aberrant Attentional Processes in Schizophrenia as Reflected in Latent Inhibition Data

Latent inhibition (LI) is demonstrated when a previously unattended stimulus is less effective in a new learning situation than a novel stimulus. Since LI is reduced by dopamine agonists and increased by dopamine antagonists, and schizophrenic patients often display attentional impairments, LI has come to play an important role in the investigation of information processing deficits in schizophrenia. The chapter reviews the rationale for this approach and summarizes the LI data from schizophrenia patients and healthy groups that are self-rated on traits related to schizophrenia (schizotypality). The review suggests that schizophrenia patients with positive symptoms exhibit attenuated LI, whereas those with negative symptoms show normal or potentiated LI. These effects are accounted for by differences in the ability to shift attention from controlled to automatic processing and the manner in which such shifts are affected by the masking task load.