Objective: Due to methodological reservations, open clinical trials investigating efficacy and tolerability of antipsychotic agents are often regarded with doubt. However, there are nearly no studies comparing findings of controlled double-blind with those of open trials. The aim of this study was to investigate whether results of open and double-blind approaches differ and thereby gain information about the validity of open trials.
Methods: After literature research, three atypical antipsychotic agents were identified for which at least three open and double-blind trials existed that met the inclusion criteria and from which either the reduction of the Brief Psychiatric Rating Scale (BPRS)- or Positive and Negative Symptom Scale (PANSS) scores or the response rate could be determined.
Results: There were no differences in the reduction of the BPRS- or PANSS scores or in the response rates for all three antipsychotic agents between open and double-blind trials.
Conclusions: Although double-blind controlled studies are essential in the investigation of new compounds, results of methodologically well-performed open studies are valid and deserve more attention. Preceding open trials may help in the design of double-blind studies.