Brief ReportsOlanzapine acute administration in schizophrenic patients increases delta sleep and sleep efficiency
Introduction
Several polysomnographic abnormalities seems to occur consistently in schizophrenic patients: impaired sleep continuity and decreased total sleep time, less amount of delta sleep, and reduced rapid eye movement (REM) sleep latency and defective REM sleep rebound following REM sleep deprivation (Keshavan et al 1990).
Decrease in delta sleep has been suggested to be the prevailing alteration in the sleep of schizophrenic patients, to be stable across nights, and to represent an abnormality of trait like character (Benson and Zarcone 1989, Keshavan et al 19902; Benson et al 1996). Also, there is some correlation between the decrease in delta sleep and ventricle size, in schizophrenic patients (Lauer and Krieg 1998).
Olanzapine is a novel antipsychotic displaying nanomolar affinity at dopaminergic D1–D4, serotonergic (5–HT 2,3,6); cholinergic, muscarinic (subtypes 1–5), adrenergic (α1), and histaminergic (H1) binding sites (Bymaster et al 1996). Also olanzapine may have some interaction with glutamatergic mechanisms, that is antagonic to phencyclidine or MK–801 in inducing behavior modeling schizophrenia (Corbett et al 1995). Because there are some anecdotal comments about the sleep promoting effect of olanzapine in schizophrenic patient, we decided to study the effects of this new antipsychotic drug in the sleep of schizophrenic patients.
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Methods and materials
Twenty schizophrenic patients were studied, 11 females, 9 males (average age: 33.6 ± 10.7 years), diagnosed after a Structured Clinical Interview for DSM-IV (SCID DSM-IV). They were drug free at least 2 weeks before entering the study, did not have antecedents of drug addiction other than nicotine, and none of the patients were on depot antipsychotics before the study. After the procedure had been fully explained, informed consent was obtained from each participant before the study began. All
Results
Twenty schizophrenic patients were studied. Ten of them were paranoid, eight undifferentiated, one catatonic and one disorganized.
Sleep variables of the twenty schizophrenic patients can be seen in Table 1. Sleep continuity variables and total sleep time (TST) had an overall improvement with olanzapine. Waking time was reduced since the first olanzapine administration (one-way ANOVA: F = 7.77, p< .001) while TST had a significant increase during the two nights with olanzapine (one-way ANOVA: F
Discussion
The major finding of the present study was an overall increase in TST with significant increase in delta sleep and sleep stage 2 since the first olanzapine night. Also there were no changes in REM sleep variables other than REM density.
Four of the twenty patients had no detectable delta sleep at all, but even in these patients there was a delta sleep enhancement. The increase in delta sleep could be related to the antagonistic properties of olanzapine on 5–HT2 serotonergic receptors.
References (10)
- et al.
Radioreceptor binding profile of the atypical antipsychotic olanzapine
Neuropsychopharmacol
(1996) - et al.
Differential effects of the new antipsychotic risperidone on sleep amid wakefulness in the rat
Neuropharmacol
(1989) - et al.
Effects of clozapine on sleepA longitudinal study
Biol Psychiatry
(1997) - et al.
5–hydroxytryptamine–2 antagonist increases human slow wave sleep
Brain Res
(1986) - et al.
Slow–wave sleep and ventricular sizeA comparative study in schizophrenia and major depression
Biol Psychiatry
(1998)