This study focused on determining whether cognitive problems were associated with depression and if they are a valuable target for treatment. Impaired cognition has been estimated to occur in about ⅔ of depressed patients. It can include an impaired ability to think, concentrate, and or make decisions. These impairments are even present in ⅓-½ of remitted depressed patients (those who experience minimal to no symptoms anymore). A prior study revealed that improvements in mood were also related to improvements in verbal memory, verbal fluency, and psychomotor speed while attention and executive function remained damaged even with treatment.
The purpose of the researchers was to conduct another review of cognitive impairments of depressed patients, during symptomatic and remitted states, through the use of the Cambridge Neuropsychological Test Automated Battery (CANTAB). They predicted that cognitive issues would be observed in both symptomatic and remitted depression states, and that would prove the need for treatment regarding cognition specifically. The CANTAB included a wide variety of tests from spatial working memory tests to reaction time. The researcher’s study met the criteria of having patients diagnosed with a major depressive disorder, a healthy control group, the CANTAB, and performing statistical tests (Cohen’s d effect sizes) to analyze the data.
The results of the study showed that currently depressed patients had significant moderate deficits compared to healthy participants in the cognitive domains of executive function, memory, and attention. Patients remitted from depression also showed significant moderate deficits compared to the healthy participants across the domains of executive function and attention.
Overall, the researchers hypothesis was supported by the results of the study since impairments in cognitive ability were shown by depressed symptomatic and remitted patients. Previous studies mention that impaired cognition has been connected to a poor response to antidepressant treatment. However, the relevance of cognitive problems also depends upon their impact on psychosocial functioning. Psychosocial functioning is a person’s ability to perform daily activities and engage with others in a gratifying and beneficial way to themselves and the community. Impaired psychological functioning is another feature of depression and it can remain in patients even after other symptoms of their depression have been remitted. There is an association between cognitive defects and impaired psychosocial functioning. These findings allowed the researchers to suggest that treating cognitive impairment in depressed patients may also help improve psychosocial functioning and overall functioning.
Source:
Rock, P. L., Roiser, J. P., Riedel, W. J., & Blackwell, A. D. (2014). Cognitive impairment in depression: a systematic review and meta-analysis. Psychological medicine, 44(10), 2029–2040. https://doi.org/10.1017/S0033291713002535
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