Positive effect of olanzapine on cognitive functions in schizophrenia was confirmed in many papers accessible in the literature.

The objective of our study is to evaluate the effect of olanzapine treatment on cognitive functions in patients suffering from schizophrenia during a six-month observation.

Twenty patients with a diagnosis of schizophrenia according to ICD-10 diagnostic criteria for research were examined. 1 day before initiation of olanzapine a baseline assessment was performed. The neuropsychological examination was repeated 28 days, 60 days, 3 months, and 6 months after the beginning of treatment. The use of benzodiazepines was interrupted 48 hours before each assessment, and a continuous co-medication with benzodiazepines never lasted longer than 48 hours. No other additional medication was administered. Cognitrone (COG) and Vienna Reaction Test (RT), both tests being a part of Vienna TEST System, were used. The Positive and Negative Symptom Scale (PANSS) was also used to evaluate general nonpsychotic psychiatric symptoms, positive psychotic symptoms, and negative symptoms. The assessment with the use of PANSS took place on the same days as the neuropsychological examination.

We have shown with the use of neurocognitive battery, that patients treated with olanzapine improved during the treatment. It is notable that this improvement was observed already on the 28th day of the treatment.

The above data here may be useful in encouraging clinicians to use olanzapine across the broad range of schizophrenic patients.