Mood and Functional Disability – A Positive Feedback Loop




Puzzle piece missing

Emotional or mood problems are more frequent in people with disabilities (of any severity or duration) than in the general population. Rates range from about 20% to 50%, depending on the study and the population – from spinal cord injury to multiple sclerosis to stroke. It is important to understand the rates and types of mood disorders because the functional deficits associated with disability (I’m using disability to refer to any sort of loss of function, even if it is only temporary) can manifest similarly to mood disorder symptoms. For example, what might look like anhedonia could simply be inability to do much, or at least the reticence to be active because of pain or functional loss.

While clinicians might accurately understand the difference between physical disability and anhedonia or any number of mood disorder symptoms, patients might not understand that difference, especially as they fill out questionnaires, which are open to the subjectivity of personal interpretation. In other words, a patient might endorse symptoms related to their injury as mood-related, even if the symptoms are not. Clinicians need to take care in order to not over-diagnose mood disorders. On the other hand, depression is common but not inevitable in people with disabilities. This means that while some of the disabling conditions might manifest similarly to symptoms of depression, for example, it is important to not minimize or miss any symptoms of a mood disorder. That’s the catch-22 of mood disorders and disability.

Do Instrumental Activities of Daily Living (IADL) deficits amplify (create or act as part of a positive feedback loop) emotional problems? The evidence presented above of higher rates of depression and other mood disorders in people with disabilities leads to the conclusion that IADL deficits can amplify mood disturbances. John Bowlby was one of the pioneers who demonstrated a link between loss and depression. It is reasonable to assume that functional loss associated with disability can amplify depressive or other mood disorder symptoms.

But do emotional problems amplify IADL deficits? There is good evidence that cognitive dysfunction is related with poorer ADL and IADL performance (Lichtenberg & MacNeill, 2000), although cognitive disturbances usually have to be quite severe to grossly impact ADLs and somewhat less severe to affect IADLs. Those who have greater cognitive problems also tend to have longer or less recovery in rehabilitation. Cognitive deficits can be a significant factor affecting whether or not functional independence is gained through rehabilitation (Lichtenberg & MacNeill, 2000).

So again, is there evidence of a link between mood and IADL impairment? Depression can predict disability onset; it also predicts mortality. This means that those who are depressed are more likely to develop disability and are more likely to die. Further, there is evidence that those who are depressed have more IADL impairments over time than those who are not depressed. Those who are depressed also show fewer functional gains in rehabilitation settings than those who are not depressed (Lichtenberg & MacNeill, 2000).

These results demonstrate a positive feedback loop between both emotional problems and IADL deficits and IADL deficits and emotional problems. It can turn into a vicious cycle unless disrupted by psychological and rehabilitative intervention. Many patients in rehabilitation settings will make functional gains, which will help their mood, but if clinicians recognize mood problems and are able to treat those mood problems, they can help facilitate better functional gains. In this way clinicians can take advantage of this positive feedback loop and utilize it to benefit those who have functional disabilities (e.g., IADL deficits).

Reference

Lichtenberg, P. A., & MacNeill, S. E. (2000). Geriatric Issues. In Handbook of Rehabilitation Psychology (Eds. R. G. Frank & T. R. Elliott). APA, Washington D.C.

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Jared Tanner, PhD

Jared Tanner has a Ph.D. in clinical psychology with an emphasis in neuropsychology. His interests are mainly neuroimaging and neuroanatomy. He spends his research time looking at the structure of gray and white matter in the brains of people with Alzheimer's disease and Parkinson's disease. With a focus on neuropsychology, he is also interested in how normal and abnormal brain structure relates to cognitive and behavioral functioning.
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