Cognitive Deficits and Functional Impairment in Major Depressive Disorder
While the Montreal Cognitive Assessment (MoCA) is recommended in the primary care setting as a screening tool for cognitive impairment, the optimal assessment of cognitive symptoms as they relate to functional impairment is an active area of interest in the field of psychiatry. Panelists consider the so-called paper-and-pencil tests such as the MoCA along with the more real-world measures, such as cognitive instrumental activities of daily living (IADL) and find value in both.
Q: What are some of the challenges in evaluating functional impairment from major depressive disorder (MDD), and how can clinicians work to achieve full functional remission?
Chief, Division of Geriatric Psychiatry
“A neuropsychological evaluation will evaluate the domains of cognitive impairment in more depth and help to differentiate between dementia syndromes and depression.”
I think of cognition and functioning as being separate entities that should be simultaneously assessed. The instruments that allow us to assess cognition are different from those that allow us to assess day-to-day functioning. The cognitive assessment tool that I would recommend in the primary care setting is the aforementioned MoCA. This is a nonproprietary instrument with a 30-point scale that assesses the major domains of cognition more thoroughly than the Mini-Mental State Examination (MMSE). The MoCA tests executive functioning, visuospatial skills, memory, language, orientation, and abstraction. The MoCA has a nice clock-drawing section, a trail-making test in which you connect letters to numbers in alternating sequences (a set-shifting test), and a visuospatial functioning test, among other sections (see figure).
The MoCA has tests of executive functioning that do not exist in the MMSE. It also assesses attention, memory, orientation, and language. So, it’s a brief, but comprehensive assessment that will objectively identify cognitive impairment in older adults with or without depression.
Functioning is assessed by the activities of daily living (ADL) and IADL measures. The IADL measure assesses functional abilities such as managing one’s own checkbook, driving, paying the bills, and going to the grocery store. The ADLs are the more basic daily living skills such as dressing, bathing, and grooming that become impaired in more severe cognitive syndromes like dementia. A neuropsychological evaluation will evaluate the domains of cognitive impairment in more depth and help to differentiate between dementia syndromes and depression.
Impaired cognitive functioning may be associated directly with impaired day-to-day functioning. A comprehensive assessment can help determine whether cognitive impairment, depression, or both are associated with the functional impairment noted. Take, for example, an individual who is not doing self-care, has reduced attention to hygiene, and is eating poorly. Do these problems stem from depression, dementia, or possibly, both? Teasing that out can be challenging to do and sometimes requires an empiric approach.
Clinical Professor of Psychiatry
I am pleased that the field is talking more about not just reducing a primary outcome score on depression severity, but also looking at recovery and embracing more of the functional, symptomatic, and syndromal aspects of outcomes.
In the real world, patients may be told, in essence, “Well, your Hamilton Rating Scale for Depression (HAM-D) score has dropped below a certain number ‒ and that’s good, but you are still not quite able to get back to work and not really functioning at home with your responsibilities.” I think this really comes up short. The more real-world outcome definitions that I see being discussed and described more in the literature bring us that much closer to the goals of treatment.
Distinguished Professor of Psychiatry Emeritus
I think that this is a very interesting issue and one that we need to deal more with (ie, the assessments of performance, on, say, cognitive IADL, performed in the home environment of the participants). Some of our occupational therapists (OTs) go into the homes of some of the participants of our clinical trials and watch them prepare meals, change a light bulb, wash clothes, go to the grocery store, and carry out a shopping list ‒ these activities that tell us a lot about how well someone is doing and whether he or she can remain functionally independent for very much longer. I think that’s what matters to patients and to their family caregivers. In our hands, this has been both a research tool and something that we are using increasingly in practice, in collaboration with our OT colleagues, in a number of different kinds of settings, such as for a patient with post-stroke depression, or one whose status is post myocardial infarction.
It’s one thing to show a paper and pencil effect, but it’s something else entirely different to show a true functional effect on how well a patient can perform cognitive IADL. And it seems to me that that is really where the field needs to go, although it is still important to do paper and pencil tests.
Mini-Mental State Examination (MMSE). http://www.dementiatoday.com/wp-content/uploads/2012/06/MiniMentalStateExamination.pdf. Accessed June 11, 2017.
Montreal Cognitive Assessment. http://www.mocatest.org/. Accessed June 11, 2017.