the role of antidepressant treatments on cognitive deficits: a review of recent literature

Abstract

Objective: Nowadays, the interaction between cognition and emotions during a depressive disorder in an area of interest in the scientific literature. Patients with major depressive disorder (MDD) usually show alterations in various cognitive functions: attention, working memory, mental processing speed, executive functions. Clinical observation of the effects of cognitive deficits on quality of life in patients with MDD, in euthymic and relapse phases, needs a review of recent scientific literature on the impact of antidepressant treatment as a protective factor of the improvement of cognitive performances. Methods: Electronic PubMed and PsycInfo searches were conducted to identify research articles that focus on the effect of antidepressant treatments in responder and non-responder patients. We searched for papers published between 2006-2011, using the following keywords: major depressive disorder, cognition, neuropsychology and antidepressants. Our working group selected fifteen main scientific articles. These are: five non-blinded clinical trials, six case-control studies, three double-blind controlled clinical trials and a prospective part-randomised trial. Results: Although some heterogenous methodological aspects, the articles show comparable characteristics, such as common evaluation tools and point out that depression is characterized by specific biases in emotional processing that include negative information processing and deficits in cognitive control. An early antidepressant drug treatment (especially SSRIs and SNRIs) may play a protective role in cognitive impairment. SNRIs seem to have a stronger effect than SSRIs on cognitive functions, that persist even after cessation of treatment during recovery. We cannot establish if a neuroprotective function is attributable only to treatment or to the natural course of depression. An appropriate drug treatment appears to be effective in improving cognitive abilities and depressive symptoms in elderly depressed patients. According to some authors, a bias in processing of appropriate stimuli varies with mood and individual history. Conclusions: Although some conflicting data, impairment is frequently reported in the acute phases of the illness: depression is associated with impairment in everyday life functions and job performance. Traditionally, that impairment is seen as an effect of affective symptoms, but it was found that improvement of depression symptoms is not associated with a similar improvement on daily activities. A cognitive training could be useful in long-term antidepressive treatment to prevent relapses and improve the quality of life. In conlusion, cognitive functions and their importance in daily life should be taken into great consideration for their functional impact on patients and the psychiatrist's choices in terms of drug and rehabilitation treatment.