Depression and Learning

What is memory?

How Depression Affects Learning— BipolarDisorderCenters.com

Cognitive Difficulties Associated with Depression: What are the Implications for Treatment?— Delgado and Schillerstrom (2009)

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article published in the Psychiatric Times that discusses the cognitive impairments associated with major depression

makes some associations between subjective complaints of those suffering from MDD (such as lack of concentration) and cognitive abnormalities (such as white matter hyperintensities)

“In younger adults, some data suggest that mental slowing and reduced motivation and attention may contribute to the apparent dysfunction in other cognitive domains. Cognitive dysfunction in younger adults tends to improve with treatment, although some patients continue to have residual mild impairment.”

article makes suggestions on how research and development of new cognitive treatments can help in alleviating some of the more severe symptoms of MDD

Implications:

Although the article does not explicitly associate depression and learning, many of the “cognitive dysfunctions” the paper focuses on are commonly associated with learning and it is subsequently easier to make a correlation.

Learning as a Model for Neural Plasticity in Major Depression—Nissen et al. (2010)

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This study investigates a novel concept in the etiology of MDD, in which researchers suggest it is a dysfunction in neural plasticity (which is what drives organisms to adapt to their environment via internal and external cues) that results in major depressive disorder

neuroplasticity hypothesis of MDD

Implicates the hippocampus, amygdala, and primary cortex in this research, three structures that have been shown to be central in learning and conditioning

“to probe plasticity, memory consolidation was assessed using three tasks for which learning has been shown to strongly depend on local synaptic refinement in brain regions of interest”

Data provides support the above hypothesis

results: “depressed subjects showed a significant deficit in declarative memory consolidation and enhanced fear acquisition"

less successful in recalling word-pairs, as well as experiencing impaired visual discrimination        

Implications:

What is learning?

Depression impairs learning, whereas the selective serotonin reuptake inhibitor, paroxetine, impairs generalization in patients with major depressive disorder-- Herzallah et al. (2013)

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In this study, researchers gave three separate groups (medication-naive patients with MDD;medicated patients with MDD; healthy controls) a computer-based cognitive task that incorporated two phases: 1. a sequence learning task via reward-based feedback and 2. a generalization phase where learned rules were to be applied.

They found that medication-naive patients were slower in learning the first phase (which was striatal-dependent) and normal on the second vs. medicated patients that were normal on the first phase and slower on the second (hippocampal-dependent).

Implications for learning:

Impaired learning for those suffering from major depressive disorder (performance was similar to that of patients with Parkinson's disease).

What is depression?