Correlation between number of episodes and neurocognitive functions during remission in major depressive disorder patients

Abstract

Objective: To compare neurocognitive functions of patients diagnosed with major depressive disorder, in remission and having undergone one or more episodes, and to examine the relationship between probable effect and number of episodes. Methods: Ninety individuals, 60 depressive disorder patients still in remission (half having experienced one episode and the other half more than one) and 30 healthy volunteers, were included. The patient and control groups were compared by means of tests measuring executive, attentional, memory and visual-spatial functions. Results: Test performances in the group that had undergone a single episode were lower than those of the control group and higher than those of the group with multiple episodes, whether the differences achieved statistical significance or not. A correlation was determined between increasing numbers of episodes and a decrease in test performances. Discussion: Permanent neurocognitive deficits may develop with every episode in depression. As episodes recur, new deficits may appear and previous ones may become more pronounced. The fact that deficits may also persist in remission suggests that these deficits are not solely a 'state-dependent' phenomenon appearing during episodic periods.