Multiple fixed doses of "Seroquel" (quetiapine) in patients with acute exacerbation of schizophrenia: a comparison with haloperidol and placebo. The Seroquel Trial 13 Study Group

Biol Psychiatry. 1997 Aug 15;42(4):233-46. doi: 10.1016/s0006-3223(97)00190-x.


Five fixed doses of the atypical antipsychotic "Seroquel" (quetiapine) were evaluated to delineate a dose-response relationship, as measured by changes from baseline in Brief Psychiatric Rating Scale (BPRS), Clinical Global Impression (CGI), and Modified Scale for the Assessment of Negative Symptoms (SANS) summary scores, and to compare efficacy and tolerability opposite placebo and haloperidol. Three hundred sixty-one patients from 26 North American centers entered this double-blind, placebo-controlled trial with acute exacerbation of chronic schizophrenia (DSM-III-R). Patients who completed a single-blind, placebo washout phase were randomized to double-blind treatment with quetiapine (75, 150, 300, 600, or 750 mg daily), haloperidol (12 mg daily), or placebo and evaluated weekly for 6 weeks. At end point, significant differences (p < 0.05, analysis of covariance) in adjusted mean changes from baseline were identified between the four highest doses of quetiapine and placebo for BPRS total, BPRS positive-symptom cluster, and CGI Severity of Illness item scores and between quetiapine 300 mg and placebo for SANS summary score. Differences between quetiapine and haloperidol were not significant. Dose-response modeling showed significant linear and quadratic functions of quetiapine dose for all primary efficacy variables. Notably, no significant safety concerns were identified as dose increased. Quetiapine was no different from placebo across the dose range studied regarding incidence of extrapyramidal symptoms or change in prolactin concentrations. Quetiapine is well tolerated and clinically effective in the treatment of schizophrenia. It is both superior to placebo and comparable to haloperidol in reducing positive symptoms at doses ranging from 150 to 750 mg/day and in reducing negative symptoms at a dose of 300 mg/day.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Antipsychotic Agents / administration & dosage
  • Antipsychotic Agents / adverse effects
  • Antipsychotic Agents / therapeutic use*
  • Dibenzothiazepines / administration & dosage
  • Dibenzothiazepines / adverse effects
  • Dibenzothiazepines / therapeutic use*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Haloperidol / administration & dosage
  • Haloperidol / adverse effects
  • Haloperidol / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Quetiapine Fumarate
  • Schizophrenia / drug therapy*
  • Schizophrenic Psychology


  • Antipsychotic Agents
  • Dibenzothiazepines
  • Quetiapine Fumarate
  • Haloperidol