Quetiapine versus olanzapine for the treatment of negative symptoms in patients with schizophrenia

Pinkhas Sirota*, Irit Pannet, Ady Koren, Eleonora Tchernichovsky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Negative symptoms are considered the most debilitating and refractory aspect of schizophrenia, being associated with poor social, occupational and global outcomes. Conventional antipsychotics have limited efficacy against these symptoms and poor tolerability profiles. Atypical antipsychotics are an alternative treatment, and this 12-week, randomised, flexibly dosed study compared the efficacy, safety and tolerability of quetiapine and olanzapine in this regard. Of the 40 patients who entered the study (32 male; 8 female), 19 were randomised to quetiapine (mean dose 637 mg/day, mean treatment duration 80 days) and 21 to olanzapine (mean dose 16 mg/day, mean treatment duration 78 days). Quetiapine and olanzapine were similarly effective: in each treatment group significant improvements at Week 12 were observed for negative symptom scores on the SANS and the PANSS, and for subscale scores of affective flattening and alogia on the SANS. Both treatments were well tolerated in this patient population, with no worsening of extrapyramidal symptoms in either case. Anxiety and insomnia were the most common adverse events (≥7% of patients in each group), but were not drug-related. Although this is a small study with limited power, the results support the effectiveness of quetiapine and olanzapine in treating the negative symptoms of schizophrenia.

Original languageEnglish
Pages (from-to)227-234
Number of pages8
JournalHuman Psychopharmacology
Issue number4
StatePublished - Jun 2006


  • Efficacy
  • Negative symtoms
  • Olanzapine
  • Quetiapine
  • Safety
  • Schizophrenia


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