Depressed mood as a transdiagnostic target relevant to anxiety and/or psychosis: a scoping review

Depressed mood is a psychological state characterised by sadness or loss of interest in activities, is a common symptom that accompanies most major mental disorders. It is therefore reasonable to consider it as a transdiagnostic target, which when addressed, may improve the functioning and quality of life of persons with lived experience of mental disorders. However, there is limited understanding of the depressed mood as a transdiagnostic target across major mental disorders. Therefore, this scoping review aims to synthesise knowledge on depressed mood, its measurement and interventions among persons with anxiety and/or psychosis.

This scoping review followed Arksey and O'Malley's framework. Peer-reviewed articles and grey literature published from January 1988 to April 2024 were searched in the following databases: Medline/PubMed, Scopus, Web of Science, Africa-Wide Information, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, SocINDEX, Humanities International Complete, Sabinet, Open Grey and Google Scholar. Articles were screened at title, abstract and full article levels. Data extracted were analysed using thematic analysis and reported following Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines. We also consulted stakeholders such as lived experience experts, clinicians and researchers to contextualise our findings.

We screened 245 full articles out of the 4039 hits and included 28 articles in this review. Although depressed mood is conceptually different from clinical depression, the terms are used interchangeably in the literature. The prevalence of depressed mood in psychosis was 7.3-33.3%, with no prevalence studies specific to anxiety disorders. Commonly used outcome measures included Beck's Depression Inventory (n=6) and Patient Health Questionnaire-9 (n=5). Psychosocial conservative interventions such as cognitive-behavioural therapy were the most common interventions. Other interventions, including yoga, pharmacotherapy and Ecology Momentary Interventions, were also reported. All interventions were reported to improve depressed mood, and most were implemented in high-income settings. Stakeholders, including lived experience experts, concurred on the importance of using depressed mood as a transdiagnostic target, viewing it as a 'window' for early identification and management of many common mental disorders.

There is a need to clarify the definition and diagnostic cut-off points on common outcome measures of depressed mood. There is also a need for increased research on depressed mood as a viable transdiagnostic target in anxiety and/or psychosis with a special focus on low-to-middle income countries.

Depressed mood is an important and prevalent transdiagnostic target with great promise for early management in anxiety and/or psychosis. Valid diagnostic and measurement tools are developing, and so are the targeted interventions in the context of anxiety and/or psychosis.