Amphetamine improves cognitive function in medicated individuals with schizophrenia and in healthy volunteers
Received 22 April 2004; received in revised form 28 December 2004; accepted 30 December 2004.
Abstract
Background
Recent research on schizophrenia indicates that cognitive deficits in this illness are important predictors of functional outcome, highlighting the need for treatments that have a positive impact on cognitive function. Here we explore the hypothesis that acute administration of d-amphetamine can improve cognitive function in individuals with schizophrenia who are well-treated with typical antipsychotics, as well as in healthy controls performing under dual task conditions designed to elicit performance deficits analogous to those found in schizophrenia.
Methods
Ten individuals with schizophrenia taking haldol or prolixin and 22 healthy controls performed spatial working memory, language production, and Stroop tasks under both placebo and 0.25 mg/kg of d-amphetamine.
Results
d-Amphetamine improved reactions times on the spatial working memory and Stroop tasks for both individuals with schizophrenia and controls, and improved working memory accuracy in schizophrenia. In addition, d-amphetamine improved language production for both individuals with schizophrenia and controls.
Conclusions
These results provide support for the hypothesis that the adjunctive administration of dopamine agonist can improve cognitive in individuals with schizophrenia taking typical antipsychotics. The results are discussed in terms of their implications for understanding the nature of working memory deficits in schizophrenia, and potential future avenues for cognitive enhancement in this illness.
aDepartment of Psychology, Washington University, United States
bDepartment of Psychiatry, Washington University, United States
cDepartment of Psychology, University of Pittsburgh, United States
dDepartment of Psychiatry, University of Pittsburgh, United States
Corresponding author. Department of Psychology, Washington University, Box 1125, One Brookings Drive, St. Louis, MO 63130, United States. Tel.: +1 314 935 8729; fax: +1 314 935 4711.
1 Department of Psychiatry and Psychology, University of California at Davis.
ABSTRACT