A Longitudinal 5-Year Follow-Up Study of Cognitive Function After First Episode Major Depressive Disorder: Exploring State, Scar and Trait Effects

Abstract

Major depression (MDD) is associated with cognitive deficits in processing speed and executive function (EF) following first episode (FE). It is unclear whether deficits are state or trait related. Studies following FE MDD over longer periods are lacking, making it uncertain how cognition and symptoms develop after the initial episode. The present study assessed cognitive function and symptoms 5 years following FE MDD. In addition, the study explored relationships between MDD symptoms, rumination, and cognitive deficits with regards to the trait, state, and scar perspective. Twenty-three participants with previous FE MDD, and 20 matched control participants were compared on Delis-Kaplan Executive Function System measures of processing speed and EF, in a 5-year longitudinal follow-up study. Correlations between current symptoms- and history of MDD, rumination, cognition were investigated. Findings indicated that cognitive deficits persisted with no clear signs of exacerbation after initial episode. Inhibition appeared independent of current and previous symptoms of depression. Processing speed was related to depressive- symptoms and rumination. In conclusion, results indicated persisting, stable deficits in both EFs and processing speed. Findings further suggest that depressive symptoms could be related to deficits in processing speed, indicating state effects. There was limited support for worsening of cognition after initial episode. Some aspects of EF like Inhibition could show persistent deficits independent of depressive symptoms indicating trait effects.

Cognitive Impairment and Neurocognitive Profiles in Major Depression—A Clinical Perspective

“…Wekking et al ( 53 ) also found persisting deficits in most cognitive measures, except inhibition. Both studies used a contrast score that only approached statistical significance and results similar to other studies ( 30 , 63 ).…”

“…This conclusion was supported in findings from several studies conducted by Schmid and Hammar ( 62 ), who stated that impaired inhibition on the stroop test, in addition to semantic fluency, is present early in the course of MDD, indicating that EF represents a trait in MDD, irrespective of symptom severity and number of previous episodes. Moreover, the authors showed that impairment in inhibition and switching and semantic fluency in first-episode MDD persisted in long-term follow up ( 63 ), with the former associated with relapse during the first year after the first episode ( 30 ), and with deficits in inhibition in a subgroup with relapse 5 years later ( 64 ), suggesting a relationship between impaired ability in EF of inhibition and switching and relapse in MDD. These findings were also evidenced in patients with recurrent depression and showed that impaired inhibition in the acute phase persisting in phases of symptom reduction ( 65 ).…”

“…Other studies consistently find EF impaired in the depressed state ( 70 , 71 ), with some inconsistencies with regards to improvements with symptom reduction ( 54 , 72 , 73 ). Pu et al ( 46 ) found small correlations between an EF composite and depressive symptoms; however, this could vary by specific EF tasks measured ( 63 ). Age could also influence EF deficits, Boedeker et al ( 74 ) found impairments in switching, but no statistically significant differences in inhibition, in an aging MDD sample.…”

The Scarring Effects of Depression Symptoms on Sadness Rumination and Peer Victimization in Greek Early Adolescents: Evidence for an Integrated Symptoms-Driven Model

“…Employing multivariate latent growth models across gender would be recommended to test for these differences more accurately (Gomez-Baya et al, 2017). The “Scar Hypothesis” of depression refers mainly to neurobiological changes, with “scars” being a result of prolonged depression episodes (e.g., Ronold et al, 2020). Given that this was a non-clinical study involving a non-clinical and non-stratified sample, interpretations are made with caution and generalizations are difficult to attain.…”

Can Daytime Transcranial Direct Current Stimulation Treatment Change the Sleep Electroencephalogram Complexity of REM Sleep in Depressed Patients? A Double-Blinded, Randomized, Placebo-Controlled Trial

“…Specifically, the annual and lifetime prevalence rates are as high as 6.6 and 16.2% ( 1 ). Recurrences leave patients with a heavy economic burden, a lower quality of life, and could be incremental ( 2 ). Between 50 and 90% of patients with depression complain about sleep disturbances ( 3 ).…”