Discrepancies from registered protocols and spin occurred frequently in randomized psychotherapy trials-A meta-epidemiologic study

J Clin Epidemiol. 2020 Dec:128:49-56. doi: 10.1016/j.jclinepi.2020.08.013. Epub 2020 Aug 20.


Objectives: This study aimed to investigate the relationship between trial registration, trial discrepancy from registered protocol, and spin in nonpharmacological trials.

Study design and setting: Recent psychotherapy trials on depression (2015-2018) were analyzed regarding their registration status and its relationship to discrepancies between registered and published primary outcomes and to spin (discrepancy between the nonsignificant finding in a study and an overly beneficial interpretation of the effect of the treatment).

Results: A total of 196 trials were identified, of which 78 (40%) had been registered prospectively and 56 (29%) had been registered retrospectively. In 102 (76%) of 134 registered trials, discrepancies between trial and protocol were present. Of 72 trials with a nonsignificant difference between treatments for the primary outcome, 68 trials (94%) showed spin. Discrepancies from protocol were less frequent in prospectively than in retrospectively registered trials (odds ratio= 0.19; 95% confidence interval [CI]: 0.07-0.52), but regarding the amount of spin, there was no difference between prospectively and retrospectively registered trials (rb = -0.12; 95% CI: -0.41 to 0.19) or between registered and unregistered trials (rb = -0.22, 95% CI -0.49 to 0.08).

Conclusion: Protocol discrepancies and spin have a high prevalence in psychotherapy outcome research. The results show no relation between registration and spin, but prospective registration may prevent discrepancies from protocol.

Keywords: Conflict of interest; Depression; Psychotherapy; Reporting bias; Review; Spin in research.

Publication types

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

MeSH terms

  • Epidemiologic Research Design*
  • Humans
  • Psychotherapy*
  • Randomized Controlled Trials as Topic / methods*