Balancing rigour and relevance in guideline development for depression: The case for comprehensive cohort studies

Purpose. Clinical guidelines for the treatment of depression have not yet realized their potential for improving the delivery of the psychological therapies within national healthcare systems. Current guidelines emphasize treatment efficacy and issues in service delivery are relatively neglected. Hence, there is a hierarchy of evidence in which randomized efficacy trials are given primacy over naturalistic (i.e. practice-based) data. Such a strategy is inadequate to address important questions about best delivery of safe and acceptable psychological therapies and exacerbates divisions between research and practice communities. Methods. Selected narrative review. Results. Both randomized controlled trials and practice-based studies have shortcomings that can be ameliorated by the adoption of practical clinical trials embedded within large cohort studies - that is, comprehensive cohort studies. Conclusions. Comprehensive cohort studies have the potential to deliver an evidence base which is both rigorous and relevant. This could satisfy the scientific community as well as allowing practitioners and service users to be fully involved and committed to the process of collecting evidence and implementing guidance. We argue this would be a sound foundation upon which to build an evidence base upon which to develop future clinical guidelines for depression.