A Canadian multicenter trial assessing memory and executive functions in patients with schizophrenia spectrum disorders treated with olanzapine.
Serial verbal learning task (explicit long-term memory) and verbal fluency (generation of a response) are tests that are usually severely impaired in schizophrenia. Despite the growing literature supporting the clinical efficacy of olanzapine, psychiatrists still question its cognitive consequences. This study assessed the efficacy of olanzapine on neurocognitive functioning. Patients (N = 134) meeting diagnostic criteria for schizophrenia, schizophreniform, or schizoaffective disorders began an 8-week, open-label olanzapine treatment at a dose of 5 mg/d, which was increased to 10 mg/d after 1 week. Daily dosage was subsequently adjusted between 5 and 20 mg/d based on individual clinical status. All previous antipsychotics were tapered and discontinued during the first 2 weeks of the study. Neuropsychologic assessments were carried out at baseline and at 4 and 8 weeks. Explicit long-term memory was assessed with the Rey Auditory-Verbal Learning Test: the average immediate recall score significantly improved (P < 0.001), as did the delayed recall score (P < 0.001). The average total score on category fluency improved from 34.6 words at baseline to 37.6 words at end point (P < 0.0001). Time on both Trail A and B making tasks significantly decreased (P < 0.0001). Lack of a control arm makes it impossible to exclude a practice effect as an explanation for the enhanced cognitive performance, although the Word List Recall test represents one of the better resources to avoid a practice effect. After switching to olanzapine, there was a statistically significant improvement of cognitive function in the 3 main domains tested and no significant worsening of any memory or executive function measure.
Stip
Emmanuel
E
Centre de Recherche Fernand-Seguin, 7331 rue Hochelaga, Montreal, Quebec, Canada H1N 3V2. emmanuel.stip@umontreal.ca
Remington
Gary J
GJ
Dursun
Serdar M
SM
Reiss
Jeffrey P
JP
Rotstein
Edward
E
MacEwan
Gordon William
GW
Chokka
Pratap R
PR
Jones
Barry
B
Dickson
Ruth A
RA
D000161:Acoustic Stimulation; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001569:Benzodiazepines; D002170:Canada; D003071:Cognition / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D008875:Middle Aged; D009483:Neuropsychological Tests; D000077152:Olanzapine; D010890:Pirenzepine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000187:drug effects*; D012559:Schizophrenia / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D014706:Verbal Learning / Q000187:drug effects; D014936:Word Association Tests
D014150:Antipsychotic Agents; D001569:Benzodiazepines; D010890:Pirenzepine; D000077152:Olanzapine