• Motor performance and cognitive function were examined in depressed patients and controls. Increasing severity of depression was strongly associated with decrements in performance in both motor and memory tasks. Greatest depressionrelated impairment was found on those cognitive and motor tasks that required sustained effort. We discuss these results in terms of a generalized deficit in the central motivational state of depressed individuals.
Cohen RM, Weingartner H, Smallberg SA, Pickar D, Murphy DL. Effort and Cognition in Depression. Arch Gen Psychiatry. 1982;39(5):593-597. doi:10.1001/archpsyc.1982.04290050061012