Schizotypy and Ketamine: what can Analogue Models tell us about Semantic Memory Impairments in Schizophrenia?
The purpose of the current study was to compare a schizophrenia group to two analogue groups (one ketamine and one high schizotypy group) to determine just how well these analogues model the semantic deficits found in schizophrenia. This study was the first Australian to employ the ketamine model of schizophrenia. It was also the first to compare these analogue models directly to a schizophrenia group so the validity of each model could be assessed.
Forty-two schizophrenia, twenty-two ketamine affected participants and twenty-three high schizotypy participants were compared on implicit and explicit semantic tasks. In both the implicit and explicit conditions, participants completed two tasks, one which examined direct semantic relationships and one which assessed indirect relationships. The results indicated that while ketamine impaired semantic performance, it was only able to model the access deficits associated with semantic impairment.
The schizotypy model, on the other hand, was able to mimic both the access and storage deficits providing the same pattern of performance as that found in the schizophrenia group. While ketamine is interesting in its ability to impair semantic access, schizotypy appears to be a superior model for semantic impairment in schizophrenia given its ability to mimic both access and storage deficits.
