The scientists said the hallucinations, delusions and emotional deficits that are features of schizophrenia can be treated by existing medicines. However, they said those medicines have limited effects on the impaired attention, memory and problem-solving that comprise the cognitive deficits of schizophrenia.

University of Pittsburgh Professor Bita Moghaddam and colleagues at the Institute for Neurodegenerative Disorders in New Haven, Conn., investigated various compounds that affect brain cells in the prefrontal cortex and hippocampus by using the chemical glutamate as a neurotransmitter.

They succeeded in identifying a specific drug that affects glutamate receptors and reverses chemically induced abnormalities in prefrontal cortical functioning.

Moghaddam said the drug "has a normalizing effect on the spontaneous activity of prefrontal cortex neurons" and the work might lead to development of drugs designed to selectively treat the cognitive deficits of schizophrenia.

The research is to be published in the journal Biological Psychiatry.