Chronic use of three types of antidepressants and their effects on memory and anxiety in male and female rats.

Abstract

The use of anti-depressants has become common in the past 20 years with users now taking them for longer periods than initially intended. There is concern about the cognitive effects chronic use may have. Previous research has shown cognitive deficits in depressed patients taking medications but is complicated by depressive symptoms. This study sets out to examine the effects of these drugs, without the influence of depressive symptoms, on short term memory and anxiety. 140 rats (70 male, 70 female) were given either high or low doses of three antidepressants (fluoxetine, reboxetine and venlafaxine) or placebo over a three week period, representing chronic use. The y-maze, open field test and emergence test were used to test short term memory and anxiety. Although memory deficits were found for male rats taking low doses of reboxetine and high doses of venlafaxine, a more notable result was a deficit in initial attention across all drugs and in both sexes. This finding provides evidence for the need to re-examine the cognitive effects of antidepressants in greater detail.