Changes in cortisol secretion and cognitive improvement during antidepressive treatment in patients with major depression: a longitudinal study

Abstract

Cognitive deficits and elevated cortisol are characteristic features of depression. Only few studies have longitudinally examined the association between reduction in cortisol secretion during treatment and improvement of cognition in depressed patients and have come to inconclusive results. Cognitive function was longitudinally examined in 52 patients with major depression (mean age = 35 ± 11 years, Hamilton Depression Rating Scale mean score = 27 ± 5) before and after 3 weeks of standardized selective serotonin reuptake inhibitor (SSRI) treatment. Salivary cortisol levels were measured on the same days at 8:00, 12:00, 16:00 and 22:00 h. A healthy control group (n = 50) matched for age, gender and years of education was examined using the same measures and time points. SSRI treatment significantly reduced salivary cortisol in patients to levels of healthy controls (repeated-measures ANCOVA, time × group interaction p = .05). In patients, reduction of cortisol correlated with improvement in cognitive function in several domains: verbal memory (r = .26, p = .09), speed of information processing (r = .50, p < .01), cognitive set-shifting (r = .34, p = .03), visuoconstruction (r = -.28, p = .07), working memory (r = .27, p = .08), and attention (r = -.25, p = .10). This was confirmed in sex- and age-adjusted linear regression analyses. Improvement of cognitive function in patients with major depression during SSRI treatment was strongly related to decreased cortisol secretion.