The importance of functional impairment to mental health outcomes: A case for reassessing our goals in depression treatment research

Abstract

Outcomes in depression treatment research include both changes in symptom severity and functional impairment. Symptom measures tend to be the standard outcome but we argue that there are benefits to considering functional outcomes. An exhaustive literature review shows that the relationship between symptoms and functioning remains unexpectedly weak and often bidirectional. Changes in functioning often lag symptom changes. As a result, functional outcomes might offer depression researchers more critical feedback and better guidance when studying depression treatment outcomes. The paper presents a case for the necessity of both functional and symptom outcomes in depression treatment research by addressing three aims–1) review the research relating symptoms and functioning, 2) provide a rationale for measuring both outcomes, and 3) discuss potential artifacts in measuring functional outcomes. The three aims are supported by an empirical review of the treatment outcome and epidemiological literatures.

Access to Services and Barriers faced by People with Disabilities: A Quantitative Survey

“…In this study, whenever functional disability was present there was a 75% likelihood of a coexisting psychosocial disability being reported. Although the direction of causation is not clear, this would be expected to be bi-directional, as psychosocial disability is known to be a risk factor for functional impairment (McKnight and Kashdan, 2009), and functional impairment has been shown to increase vulnerability to psychosocial disability (Lenze et al, 2001). The high prevalence of psychosocial impairment potentially hides participation, access to services and barriers for those with functional disabilities.…”

The effect of vortioxetine on overall patient functioning in patients with major depressive disorder

“…The effectiveness of MDD treatment in relation to functional outcomes is potentially confounded by the bidirectional relationship of depressive symptoms and functional impairment, as well as by premorbid functioning, which may not be accounted for when assessing the reduction in functional impairment (McKnight & Kashdan, 2009). The National Comorbidity Survey Replication found that 96.9% of patients with MDD for at least 12 months also suffered from functional impairment (in at least one area) associated with their depression, with 19.1% of patients reporting their impairment as “very severe” (Kessler et al., 2003).…”

Mental disorder in limb reconstruction: Prevalence, associations and impact on work disability

“…It is probable that there is a bidirectional relationship between mental disorder and work disability. [38] The study was also limited by the single-centre design in specialised tertiary unit. It is possible that the results would be different in a less well-established service, or might vary geographically.…”