Improvement in cognition associated with novel antipsychotic drugs: a direct drug effect or reduction of EPS?

Background: Administration of novel, versus classic, antipsychotic agents to patients suffering from psychosis is associated both with moderately better scores on cognitive tests, and with fewer extrapyramidal symptoms (EPS). Because improved motor functioning may enable better performance on some components of cognitive test batteries, and because the advantages of the novel antipsychotics on cognitive performance are not very large, it is sometimes difficult to discern if improvement in a given cognitive task is due to a direct effect of the novel antipsychotic drug, or is secondary to the novel drug's decreased propensity to induce EPS. In an attempt to distinguish between these two possibilities, the present study examined the ability of patients suffering from schizophrenia receiving classic, versus novel antipsychotics, to perform a computerized visuo-motor test (VMT).