Introduction: It is widely accepted that major depressive disorder (MDD) is associated with impairments in several cognitive domains in inpatients, but cognitive functioning has barely been systematically investigated in depressed outpatients. The aims of the present study were to examine cognitive functioning in depressed outpatients in comparison with healthy controls and to determine whether cognitive deficits vary as a function of different disorder characteristics and demographic variables. Method: We compared 103 outpatients with recurrent MDD in an acute phase of the illness with 103 healthy controls matched on age, gender, and education level using a neuropsychological battery covering the domains of processing speed, attention, memory, working memory, and executive functions. Results: Depressed outpatients were found to be impaired in all five assessed cognitive domains. These impairments varied as a function of the disorder characteristics, particularly severity of depression, intake of medication, age of depression onset, duration of current episode, and rumination as a psychological variable as well as age, premorbid intelligence, and education level as demographic variables. Conclusions: In the present study we tried to systematically investigate the impact of different disorder characteristics and demographic variables on the cognitive dysfunction of outpatients with MDD. The results indicate a moderate to severe cognitive impairment of outpatients with MDD and reveal an influence of different disease characteristics as well as demographics. These cognitive impairments may affect the course of the disease and should be considered in outpatient therapy.
Keywords: Major depression; cognitive functioning; cognitive impairments; outpatients.