Low dissemination rates, non-transparency of trial premature cessation and late registration in child mental health: observational study of registered interventional trials

The aim of this observational study was to explore trial premature cessation, non-publication and trial registration time in child mental health. Data were extracted for “closed” trials in Clinicaltrials.gov registry and European Union Clinical Trial Register (EUCTR) and corresponding publications of completed trials indexed in three data bases (PubMed, Scopus and Google Scholar). We restricted the extraction to the ‘Behaviours and Mental Disorders’ category and participants’ age of 0–17 years. Outcome measures were trial completion, results reporting within a year after the trial completion, publishing an article in a peer-reviewed journal within an average time to publish (729 days), and registration time. The number of EUCTR trials was relatively small (n = 35) and with many inconsistencies. Out of 827 “closed” trials extracted from ClinicalTrials.gov, 69% were completed, 24.2% of prematurely ceased trials did not report reasons for early termination, 12.2% of the completed trials had results reported within a year, and 29.3% had an article published within 24 months after completion. Middle-sized (100–499 participants) and behavioural trials had higher chances of being successfully completed. Middle-sized and industry-funded trials were associated with results reporting. Chances for publishing an article were lower for industry-funded trials. Industry funding and drug interventions were related to timely registration. Large sample and non-industry funding were related to retrospective registration, which was recorded more often in recent years than before (we observed trials registered from 2002 until 2017). This study found low dissemination rates in the field of child mental health, with worrying under-reporting of premature termination causes. These findings indicate that more children are being subjected to unnecessary risk that comes with trial participation.