Is mandatory prospective trial registration working? An update on the adherence to the International Committee of Medical Journal Editors guidelines across five psychiatry journals: 2015-2020

Objective Previous research indicated that the International Committee of Medical Journal Editors guidelines of prospective trial registration with clearly identified primary and secondary outcome measures are only adhered to in 14.4% of studies published in the top five psychiatry journals between 1 January 2009 and 31 July 2013. This study examined if adherence has improved. Methods The registration information, article information, primary outcome measures (POMs), participant numbers and funding source were extracted from studies published in the same five psychiatry journals between 1 January 2015 and 31 December 2019. Discrepancies between POMs in the articles and registry were tracked. Results Of the 7268 publications, 268 studies required registration. Three (1.1%) were unregistered, 107 (39.9%) were retrospectively registered, and 158 (58.9%) were prospectively registered. Of the 158 prospectively registered studies, 16 (10.1%) had unclear POMs in the article or registration, 22 (13.9%) had discrepancies between registered and published POMs, and 33 (20.9%) had no POM discrepancies but had retrospectively updated POMs in the registry. Of the 22 studies with discrepancies, nine (40.9%) were determined to favour statistically significant results. Overall, 87 (32.5%) of the 268 studies were prospectively registered with no discrepancies between registered and published POMs and no changes to registered POMs or timeframes. Conclusion Although this rate of one third of published articles fully adhering to the guidelines is an improvement compared to previous research, further efforts still need to be made by both authors and journals to ensure full transparency in the reporting of studies in psychiatry.