Enduring cognitive dysfunction in unipolar major depression: A test–retest study using the Stroop paradigm

Abstract

The aim of the study was to investigate automatic and effortful information processing with the Stroop paradigm in a long term perspective in patients with major depressive disorder (MDD). Patients were tested at two test occasions: at inclusion with a Hamilton Depression Rating Scale (HDRS) score >18, and after 6 months, when most patients had experienced symptom reduction. The Stroop paradigm is considered to measure aspects of attention and executive functioning and consists of three conditions/cards: naming the color of the patches (Color), reading of the color-words (Word) and naming the ink color of color-words (Color-Word). The Color-Word condition is proved to be the most cognitive demanding task and requires the proband to actively suppress interference and is therefore considered to require more effortful information processing, whereas naming the color of the patches and reading the color-words are expected to be more automatic and less cognitive demanding. A homogenous group of 19 patients with unipolar recurrent MDD according to DSM-IV and a HDRS score of >18 were included in the study. A control group was individually matched for age, gender and level of education. Depressed patients performed equal to the control group on the Color and Word cards at both test occasions. However, the patients were impaired compared with the control group on the Color-Word card task at both test occasions. Thus, the depressed patients showed no improvement of effortful attention/executive performance as a function of symptom reduction. The results indicate that the depressed patients showed impaired cognitive performance on cognitive demanding tasks when symptomatic and that this impairment prevailed after 6 months, despite significant improvement in their depressive symptoms.

Executive functions in major depressive disorder

“…Poor performance on the DSST and DVT i.e., 30% and 32% respectively, and poorer performance on the Stroop test in the present sample is in line with existing literature (14,15,16,17). But some other studies have reported no difference in performance of executive functions between depressed and control groups (18,19).…”

Executive Function Impairments in Patients with Depression

“…As for D-KEFS Verbal Fluency, there were also found significant differences between groups F(3,44)=3.202; p= 0.032; Wilks' Lambda=0.82, partial eta-squared=0. 18. As for the D-KEFS Tower Test and D-KEFS Trail Making Test, no significant differences were found between groups.…”

“…Results showed a performance impairment in the patients in the two periods of evaluation, showing an effect in the group F(1,36)=7.51; p<0.05; g2=0.18 but no association to the severity/course of the disorder [18]. A comparative study was conducted including 23 female patients, aged between 46 and 82 years and diagnosed with recurrent MDD, and 60 healthy age-matched females aged between 45 and 85 years.…”

White matter correlates of impaired attention control in major depressive disorder and healthy volunteers

“…Two meta-analyses by Zakzanis, Leach, and Kaplan (1998) and Snyder (2013) found greater Stroop interference in major depressive disorder (MDD) with effect sizes of 0.63 and 0.39, respectively; a comparable effect size to what we reported (Keilp, Gorlyn, Oquendo, Burke, & Mann, 2008). Furthermore, greater Stroop interference is present during an episode of major depression, as well as in remitted depressed patients (Hammar et al, 2010; Paradiso, Lamberty, Garvey, & Robinson, 1997; Trichard et al, 1995). A greater interference effect predicts poorer response to antidepressant treatment (Dunkin et al, 2000; Sneed et al, 2007).…”