The aim of this study is to evaluate the therapeutic effect of escitalopram (cipralex) in the treatment of negative symptoms in schizophrenic patients receiving either typical or the newer atypical antipsychotics (olanzapine and risperidone) in a double-blind placebo-controlled study. As there is no drug treatment that is considered as first-line treatment in the treatment of negative symptoms, we thought that the comparison with placebo is plausible. However, it is important to note that the patients will receive the commonly used treatment for their disorder (i.e. antipsychotic medication).