A top priority for individuals with major depressive disorder (MDD) is to be able to perform at their usual level at work, as well as in their social life and leisure activities, family life and home responsibilities, and interpersonal relationships.1
To address this functional priority for patients, Roger McIntyre, Professor of Psychiatry and Pharmacology, University of Toronto, and Head of the Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, Canada said that the primary therapeutic objective in MDD must therefore be a full functional recovery.2
Functional impairment is mediated by multiple cognitive domains, including attention, memory, processing speed and executive function;3 and almost 90% of patients with MDD report moderate, severe or very severe functional impairment.4,5 However, even when other symptoms of depression have resolved, individuals with MDD continue to show impaired executive function, memory and attention.6
To achieve a full functional recovery, it is critical to identify and address the cognitive symptoms of MDD
To achieve a full functional recovery, it is critical to identify and address the cognitive symptoms of MDD, said Professor McIntyre. He noted that the US Medicaid guidelines for MDD now recommend an evaluation of cognition, as well as functional outcome.
Professor McIntyre highlighted research showing that cognitive symptoms account for more variability in workplace impairment than total depression severity;7 and that workplace functioning is mediated by mood and cognitive symptoms in adults with diabetes.8
Cognitive symptoms account for more variability in workplace impairment than total depression severity
The impact of depression on the workplace was also mentioned by John Harrison, Associate Professor at the Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands. He cited research showing that the high economic burden of MDD is largely driven by workplace productivity losses,9 attributed to absenteeism or decreased productivity.10
Standard depression scales do not assess all cognitive domains
Despite the importance of identifying and addressing cognitive symptoms to achieve a full functional recovery for patients with MDD, all cognitive domains are not assessed by standard depression scales. These scales include the Hamilton Depression Rating Scale (HAM-D), the Montgomery-Åsberg Depression Rating Scale (MADRS), the Beck Depression Inventory and the Patient Health Questionnaire.
All cognitive domains are not assessed by standard depression scales
Professor Harrison’s presentation focused on how best to identify and measure cognitive impairment. Although many options are available, he explained that comprehensive cognitive testing is restricted by availability, cost, administration time and the need for specialist interpretation of the results. Subjective cognitive scales are a practical alternative for clinical settings, but the correlation between subjective and objective measures of cognition is limited.11 In addition, cognitive decline can occur in an individual without falling outside the ‘normal’ cognitive performance range.12
Common, marked characteristic cognitive deficits in MDD affect working memory, executive function, episodic memory and processing speed13
The THINC-it® tool has therefore been developed and recently validated14 to meet the need for a comprehensive and reliable tool to assess, monitor and address cognitive functioning in MDD. It is the first freely available, self-administered, computerized screening tool for assessing cognition in MDD.15
Professor Harrison demonstrated how to use THINC-it® to identify and measure cognitive deficits using five gamified and computerized tests: 1. the Perceived Deficits Questionnaire for Depression five-item version (PDQ-D5), a self-report questionnaire about cognition; 2. the “Spotter,” a reaction time test of attention; 3. the “Symbol Check,” which tests working memory; 4. the “CodeBreaker,” a coding test that measures attention and executive function; and 5. the “Trails,” which measures executive function.
The ultimate goal in managing MDD is to treat to full functional recovery
Bernhard Baune, Professor and Chair of Psychiatry, University of Adelaide, Adelaide, Australia, explored the non-pharmacological and pharmacological approaches for treating MDD, with the ultimate goal of achieving full functional recovery.
Comprehensive management of depression will probably require a combination of pharmacological therapies with other approaches to address all emotional and cognitive aspects
He described how observational studies provide real-world evidence of the impact of cognitive symptoms in the clinic and support the importance of cognitive symptoms as a treatment target in MDD to improve daily function and overall outcomes.
With proper recognition in the clinic, cognitive symptoms can be addressed effectively, allowing for a more complete functional recovery for the patient and thus improving their overall quality of life.