Effect of Quetiapine on Negative Symptoms and Cognition

Efficacy of Quetiapine Compared to Risperidone on Negative Symptoms and Cognition With Regard to Underlying Neurobiological Mechanisms and Brain Activation.

The purpose of the study is to investigate the outcome on negative symptoms of schizophrenic patients during therapy with quetiapine or risperidone.

Inclusion Criteria:

• Signed informed consent
• men and women aged 18 to 65 years with diagnosis of schizophrenia
• score of at least 4 CGI, PANSS negative subscale score > 21
• fulfil the criterion to be right-handed for inclusion in the fMRI investigations

Exclusion Criteria:

• Substance or alcohol dependence
• female patients who are pregnant, lactating or at risk of pregnancy
• history of organic CNS-trauma, epilepsy, meningoencephalitis, psychosurgery, instable somatic conditions
• risk of suicide or aggressive behaviour
• history of electroconvulsive therapy, Parkinson's disease, Prolactin-dependent tumor

For the subset of subjects for the fMRI investigations the following additional exclusion criteria is valid as:

• existence of metal in the body as by cardiac pacemaker, coil, total prosthesis, metal splinter, metal articulation, metal balls.