 The persistent cognitive deficits which can be appreciated across the course of SZ, from prodromal to chronic SZ, may be the most important underlying dysfunction in preventing functional, occupational, and social recovery in SZ compared to other symptom domains. There is no effective treatment for these cognitive deficits which persist after antipsychotic medication has reduced or resolved the positive symptoms of SZ. Although some exploratory studies of nicotinic agonist drugs showed promise for improvement of cognitive deficits associated with SZ , later larger and better-controlled studies with nicotinic agonist drugs have not shown markedly positive effects for this type of pharmacologic intervention, although one recent study is promising. 