Cognitive function in mild to moderately depressed and previously depressed individuals

Abstract

The present study explored differences between groups of Never Depressed (ND, n = 50), Previously Depressed (PD, n = 81) and Clinically Depressed (CD, n = 38) individuals with mild to moderate depression severity on tests of executive functions, working memory, memory, attention, and psychomotor speed and information processing. The most striking finding was the absence of significant differences between the CDs and NDs on the majority of tests. The CDs had significantly poorer performance than the other groups on working memory and one measure of psychomotor speed and information processing. The PDs did not differ significantly from the other groups on the vast majority of measures. This result supports the view that cognitive impairment in depression is reversible and state dependent, and recovers upon remission from depression. There were no significant differences between CDs and PDs with 2 or less depressive episodes versus those with 3 or more episodes, and, furthermore, increased depressive severity was not associated with cognitive impairment. The results suggest that cognitive impairment in mild to moderate depression is limited and recovers as depression remits.