Thought disorder, working memory and attention: interrelationships and the effects of neuroleptic medications

Impairments in attention and vigilance, working memory and organization of speech (thought disorder) have been reliably observed in patients with schizophrenia. The response in these cognitive parameters to neuroleptic medications can be used to sharpen their characterization in neuropsychological terms. In particular, a review of the literature suggests that while working memory is relatively insensitive to neuroleptics, attention and thought disorder may improve with neuroleptic administration. On the basis of the response to typical and atypical neuroleptics, attention as deployed in the Continuous Performance Test may reflect response readiness rather than actual vigilance. Thought disorder, which is often assumed to be the result of impaired discourse planning due to a reduced capacity for working memory, does not covary with working memory, and the two parameters show different responses to neuroleptic medications. Rather, cognitive studies suggest that thought disorder may arise from abnormalities within the semantic system itself.