Low delta sleep predicted a good clinical response to olanzapine administration in schizophrenic patients

Introduction. Schizophrenic patients show sleep abnormalities, consisting mainly of decreased delta sleep time, short rapid eye movement (REM) sleep latency, and a reduction in sleep continuity variables. Olanzapine is a novel antipsychotic drug with an atypical profile. The goals of the present study were to determine if pre-treatment sleep variables and the initial response to olanzapine administration on the sleep variables can predict the clinical improvement after eight weeks of treatment. Material and methods. Twenty-one schizophrenic (DSM-IV) patients were studied. They were clinically evaluated using the positive and negative syndrome scale (PANSS), and the Calgary Depression Scale for Schizophrenia. Sleep recordings were as follows: one acclimatization nigh, one night of baseline recordings, and two nights in which the patients receives olanzapine 10 mg, one hour before bedtime. For sleep-comparison purposes, a group of normal volunteers were also studied with acclimatization and baseline nights. After the sleep recordings ended patients continued with the administration of 10 mg/d of olanzapine, that was titrated as needed up to 20 mg/d or down to 5 mg/d. Evaluations were conducted weekly. Results. Awakening and sleep latency variables were significantly higher in schizophrenic patients compared to normal volunteers. Delta sleep was lower in patients than in normal subjects, with no detectable values in some of the schizophrenics. There was not correlation at baseline, between psychopathological scores and delta sleep or other sleep variables. The acute administration of olanzapine 10 mg produced an improvement in continuity sleep variables as well as increase in deltas sleep percentage. Having less than 10% of delta sleep at baseline predicted a good clinical outcome. Eleven of 18 patients showed good clinical improvement after eight weeks of treatment with olanzapine, those were the subjects that had an augmentation of delta sleep above 10% with the first two doses of olanzapine, with minimal side effects. Conclusions. To have low delta sleep at baseline and the effect of the augmentation of this variable in schizophrenic patients seems to predict a good response to olanzapine. Olanzapine was therapeutically useful, well-tolerated medication, with a favorable safety profile.