Beyond usual care: A Realist Synthesis of primary care naturalistic longitudinal depression cohort studies

Context: Over the past 40 years, access to and efficacy of ‘usual care’ depression interventions (pharmacotherapy and psychotherapy) has steadily improved yet over the same time, depression prevalence rates have remained stubbornly high. Termed the ‘Treatment-Prevalence Paradox’, here we conducted a realist synthesis of participant self-report evidence from primary care naturalistic longitudinal depression cohort studies to try and understand why.

Objective: To form a set of insights and recommendations for depression interventions beyond that of ‘usual care’.

Study Design & Analysis: A realist synthesis is a theory-driven interpretive approach for studying complex intervention using context-mechanism-outcome configurations (CMOC) to understand “what works for whom, in what circumstances, in what respects, and how?”

Setting & Population Studied: MEDLINE, CINAHL, and PsycInfo were searched for the following articles (i) observational cohort studies (ii) participants were adult primary care patients (iii) participants were recruited from the primary care setting (iv) participants were screened for depressive symptoms and severity and/or administered a depression diagnostic interview at inclusion (v) followed up for at least 12 months. Additional articles were identified via citation searches, and the authors’ library.

Outcome Measure: The drivers of depression outcomes beyond usual care.

Results: Of the 2095 record retrieved from the database search, 76 articles were retained and a further 109 articles were identified from secondary references. A total of 185 peer-review quantitative and qualitative articles from 16 distinct cohorts, representing 53 cumulative years of observation and over 26,000 participants from 26 countries, were synthesized. The driving influence of social determinants and lived experience on depression onset and recovery were recurrent themes across the cohorts.

Conclusion: A realist synthesis of naturalistic longitudinal depression in primary care cohort studies provides for a rich and nuanced understanding of “what works for whom, in what circumstances, in what respects, and how?” with regard to interventions for people living with depression (context). A reframing of depression outcomes from ‘risk’ and ‘protective’ factors into ‘burden’ and ‘resilience’ factors (mechanism) provides insight into why we see the ‘Treatment-Prevalence Paradox’ and recommends the development of next-generation interventions (outcomes).