An analysis of the effect of funding source in randomized clinical trials of second generation antipsychotics for the treatment of schizophrenia

Control Clin Trials. 2004 Dec;25(6):598-612. doi: 10.1016/j.cct.2004.09.002.


Objective: The effect of funding source on the outcome of randomized controlled trials has been investigated in several medical disciplines; however, psychiatry has been largely excluded from such analyses. In this article, randomized controlled trials of second generation antipsychotics in schizophrenia are reviewed and analyzed with respect to funding source (industry vs. non-industry funding).

Method: A literature search was conducted for randomized, double-blind trials in which at least one of the tested treatments was a second generation antipsychotic. In each study, design quality and study outcome were assessed quantitatively according to rating scales. Mean quality and outcome scores were compared in the industry-funded studies and non-industry-funded studies. An analysis of the primary author's affiliation with industry was similarly performed.

Results: Results of industry-funded studies significantly favored second generation over first generation antipsychotics when compared to non-industry-funded studies. Non-industry-funded studies showed a trend toward higher quality than industry-funded studies; however, the difference between the two was not significant. Also, within the industry-funded studies, outcomes of trials involving first authors employed by industry sponsors demonstrated a trend toward second generation over first generation antipsychotics to a greater degree than did trials involving first authors employed outside the industry (p=0.05).

Conclusions: While the retrospective design of the study limits the strength of the findings, the data suggest that industry bias may occur in randomized controlled trials in schizophrenia. There appears to be several sources by which bias may enter clinical research, including trial design, control of data analysis and multiplicity/redundancy of trials.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antipsychotic Agents / economics*
  • Antipsychotic Agents / therapeutic use*
  • Benzodiazepines / economics
  • Benzodiazepines / therapeutic use
  • Clozapine / economics
  • Clozapine / therapeutic use
  • Dibenzothiazepines / economics
  • Dibenzothiazepines / therapeutic use
  • Double-Blind Method
  • Drug Industry / economics*
  • Humans
  • Olanzapine
  • Piperazines / economics
  • Piperazines / therapeutic use
  • Quetiapine Fumarate
  • Randomized Controlled Trials as Topic / economics*
  • Randomized Controlled Trials as Topic / methods
  • Research Support as Topic*
  • Retrospective Studies
  • Risperidone / economics
  • Risperidone / therapeutic use
  • Schizophrenia / drug therapy*
  • Schizophrenia / economics*
  • Thiazoles / economics
  • Thiazoles / therapeutic use
  • Treatment Outcome


  • Antipsychotic Agents
  • Dibenzothiazepines
  • Piperazines
  • Thiazoles
  • Benzodiazepines
  • Quetiapine Fumarate
  • ziprasidone
  • Clozapine
  • Risperidone
  • Olanzapine