Psychological interventions for epilepsy: How good are trialists at assessing their implementation fidelity, what are the barriers, and what are journals doing to encourage it? A mixed methods study.

Introduction: Psychological interventions hold promise for the epilepsy population and continue to be trialed to determine their efficacy. Such interventions present opportunities for variance in delivery. Therefore, to accurately interpret a trial's estimate of effect, information on implementation fidelity (IF) is required. We present a novel 3-part study. Part 1 systematically rated trials for the extent to which they reported assessing whether the intervention was delivered as intended (adherence) and with what sort of skill (competence). Part 2 identified barriers to reporting and assessing on fidelity perceived by trialists. Part 3 determined what journals publishing epilepsy trials are doing to support IFs reporting.

Methods: Articles for 50 randomized controlled trials (RCTs)/quasi-RCTs of psychological interventions identified by Cochrane searches were rated using the Psychotherapy Outcome Study Methodology Rating Form's fidelity items. The 45 corresponding authors for the 50 trials were invited to complete the 'Barriers to Treatment Integrity Implementation Survey'. 'Instructions to Authors' for the 17 journals publishing the trials were reviewed for endorsement of popular reporting guidelines which refer to fidelity (Consolidated Standards of Reporting Trials (CONSORT) statement or Journal Article Reporting Standards [JARS]) and asked how they enforced compliance.

Results: Part 1: 15 (30%) trials reported assessing for adherence, but only 2 (4.3%) gave the result. Four (8.5%) reported assessing for competence, 1 (2.1%) gave the result. Part 2: 22 trialists - mostly chief investigators - responded. They identified 'lack of theory and specific guidelines on treatment integrity procedures', 'time, cost, and labor demands', and 'lack of editorial requirement' as "strong barriers". Part 3: Most (15, 88.2%) journals endorsed CONSORT or JARS, but only 5 enforced compliance.

Conclusions: Most trials of psychological interventions for epilepsy are not reported in a transparent way when it comes to IF. The barriers' trialists identify for this do not appear insurmountable. Addressing them could ultimately help the field to better understand how best to support the population with epilepsy.