A randomized controlled trial of olanzapine versus haloperidol in the treatment of primary negative symptoms and neurocognitive deficits in schizophrenia.

OBJECTIVE: Primary negative symptoms are intrinsic to the pathology of schizophrenia and are associated with significant deficits in motivation, verbal and nonverbal communication, affect, and cognitive and social functioning. Overall, atypical antipsychotic medications have been found to be more efficacious than conventional antipsychotics in the treatment of negative symptoms, based on studies with acute patients. Results have been confounded by concomitant improvements in positive, depressive, and extrapyramidal symptoms. This 12-week, double-blind, controlled study aimed to examine the effects of the atypical antipsychotic olanzapine versus haloperidol on persistent, primary negative symptoms and neurocognitive functions in stable schizophrenic patients with the deficit syndrome and low levels of concomitant positive, depressive, and extrapyramidal symptoms.

METHOD: Thirty-five patients with DSM-IV-TR schizophrenia and predominant negative symptoms were randomly assigned in a 12-week double-blind study to either olanzapine (15-20 mg/day) or haloperidol (15-20 mg/day). Patients taking haloperidol received additional blinded benztropine. Inclusion criteria were Positive and Negative Syndrome Scale (PANSS) negative score of >or=20, PANSS positive score < 20, and fulfilling the criteria for the Schedule for the Deficit Syndrome. The PANSS, Clinical Global Impressions, Hamilton Rating Scale for Depression (HAM-D), Simpson-Angus Scale, and Abnormal Involuntary Movement Scale were assessed at regular subsequent intervals. A neuropsychological battery examining declarative verbal learning memory, attention and processing speed, executive functioning, and simple motor functioning domains of cognition was assessed at baseline and endpoint. The study ran from September 1998 through May 2005.

CLINICAL RESULTS: There was a statistically significant difference for PANSS negative symptoms (F = 5.44, df = 1,15; p
CONCLUSIONS: The results of this study suggest that olanzapine treatment was associated with significant improvement in primary negative symptoms, overall symptomatic improvement as measured by the PANSS total score, and improvement in some areas of neurocognition as compared with haloperidol/benztropine mesylate treatment.