The role of cognitive impairment in general functioning in major depression

The association between cognitive performance and general functioning in depression is controversial. The present study evaluated the association between cognitive dysfunction and major depressive disorder (MDD, N=70) as compared with age- and gender-matched healthy controls (n=206) and its relationship to general functioning (physical and mental health quality of life, activities of daily living, and employment status) in participants with current MDD (n=26) and those with previous MDD only (n=44). Participants were assessed clinically using the Mini International Neuropsychiatric Interview (M.I.N.I.) for the depression groups and the Diagnostic Interview for Psychoses (DIP-DM) for the control group. Measures to evaluate cognition and quality of lifes comprised the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Short Form-36 Health Survey Questionnaire, and the Activities/Instrumental Activities of Daily Living (ADL/IADL); employment status was also assessed in MDD. The results showed that a) while individuals with current depression had worse cognitive performance in all domains than healthy controls, those individuals with previous depression had lasting cognitive impairments in the domains of immediate memory and attention as compared with healthy controls; b) individuals with current depression had lower scores in the visuospatial/constructional and attention domains and the total score than individuals with previous depression; c) individuals in the depression group as a whole who were currently unemployed had significantly lower scores in all domains (except attention) of cognitive function; d) cognitive function was not related to either physical or mental quality of life or impairments of activities of daily living (ADL, IADL); e) that unemployment in previous depression was related to poor cognitive function similar to those with current depression. The results indicate that MDD may have detrimental and lasting effects on cognitive performance partly related to poorer general functioning.