Working Memory in Patients with Major Depressive Disorder

Abstract

Objective: Patients with major depressive disorder (MDD) have been reported to perform less well in neurocognitive tests than normal control subjects. The author tested the hypotheses that verbal working memory (WM) is predictive of the functional outcome in patients with MDD. Methods: In this naturalistic longitudinal study, the subjects consisted of 22 adult outpatients receiving paroxetine as antidepressant therapy. Functional outcome was rated on a scale of 0 (non-impaired) to 3 (severely impaired). Results: 1) At 12 weeks, nine of the 22 patients currently experiencing MDD exhibited full remission; 2) significantly decreased 7-item Hamilton Rating Scale for Depression (HAM-D7) scores were observed during the 12-week study period, while Digit Sequencing Task (DST) scores increased significantly; 3) at baseline, functional outcomes correlated significantly with HAM-D7 scores, but, at 12 weeks, correlated significantly with both HAM-D7 and DST scores. Furthermore, when looking at only patients in full or partial remission (mild depression), functional outcome correlated more strongly with DST than with HAM-D7 scores. Conclusions: A deficit of verbal WM correlated with the functional outcome after treatment in patients with MDD. Antidepressant therapy with paroxetine might contribute to improvement of verbal WM.

Predictors of response in the treatment of moderate depression

“…Two studies have associated working memory function with depression treatment outcome. 14,17 Similarly, it has been reported that lower attention predicts poorer response to depression treatment. 37 These findings suggest that patients who are less impaired in functions such as working memory and attention have a better prognosis, regardless of the type of treatment they are receiving.…”

“…25 The BDI measures severity of depression and classifies results as minimal (score, 0-11), mild (score, [12][13][14][15][16][17][18][19], moderate (score, 20-35), or severe (score, 36-63).…”

“…These findings showed that alternative treatments were beneficial to some patients, while cognitive psychotherapy was beneficial to others. 10 Until recently, only minor attention had been given to neurocognitive performance as a moderator of treatment outcome in studies on depression, 14 despite studies on the association between cognitive variables and depressive symptoms. 15,16 Some authors have described the relevance of neurocognitive variables for predicting symptomatic improvement.…”