BACKGROUND: Cognitive impairments, such as memory deficits and executive impairment, are common among patients with major depressive disorder (MDD) and can be captured with objective or subjective assessments. The aim of this post-hoc analysis of the CONNECT study was to assess the degree of overlap between subjective and objective cognitive impairment among MDD patients, and to evaluate associated clinical characteristics.
METHODS: The study was conducted from April 2012 to February 2014 and enrolled a total of 602 patients with MDD who reported subjective cognitive impairment. Efficacy was assessed using a battery of objective tests of cognitive function representing multiple domains: Digit Symbol Substitution Test performance, Trail Making Test A, Trail Making Test B, Congruent and Incongruent Stroop Test, Groton Maze Learning Test, Detection Task, Identification Task, and One-Back Task. The Cognitive and Physical Functioning Questionnaire (CPFQ) was used to capture patient-reported assessments of cognitive function.
RESULTS: Although 48% of patients with MDD met our conservative criteria for subjectively defined marked cognitive impairment, 64% of patients with MDD met our conservative criteria for objectively defined cognitive impairment. Therefore, the proportion of patients defined as having impaired cognition was somewhat similar regardless of methodology. Overall, 80% of patients with MDD in this study reported either subjective or objective cognitive impairment per subjective and objective scales. However, the proportion of patients meeting criteria for both subjectively and objectively defined cognitive impairment was only 31%. This could be explained by the fact that the CPFQ total score was only modestly—although significantly—correlated with all but one of the objective tests..
CONCLUSIONS: This post-hoc study shows that approximately 80% of patients with MDD participating in an antidepressant trial reported either subjective or objective cognitive impairment.