Executive dysfunction and treatment response in late-life depression
Executive dysfunction in geriatric depression has been shown to predict poor response to antidepressant medication. The purpose of this review is to clarify which aspects of executive functioning predict poor antidepressant treatment response.
From our review, the aspects of executive functioning that appear to be associated with antidepressant response rates are verbal fluency and response inhibition. There is some indication that the semantic strategy component may account for the effects of verbal fluency, although evidence comes from one study and needs replication. Processing speed has been proposed as a substrate that may underlie the effects of executive dysfunction on treatment response. Although processing speed does not appear to account for the relationship between response inhibition and treatment outcome, this issue has yet to be assessed with respect to verbal fluency.
Verbal fluency and response inhibition are specific aspects of executive dysfunction that appear to impact antidepressant response rates. Disruption of the frontostriatal limbic circuit (particularly the anterior cingulate and dorsolateral prefrontal cortex) may explain the relation between these two mechanisms.
Available from: Rodney Swenson
- "Given internal cuing may require selfinitiated cognitive processes including executive, attention and perceptual processing speed (Hoffstaedter et al., 2012), we further hypothesized that cognitive Think times would be lower relative to motor Ink times, and primarily in the older depressed group. We based our hypothesis regarding the older depressed group on studies showing deficits on tasks that incorporate aspects of psychomotor slowing, i.e., perceptual processing, programming and motor speed in a similarly aged depressed cohort (Butters et al., 2004; Nebes et al., 2000; Pimontel et al., 2012). We also explored associations between Think and Ink time variables to indices of cognitive functioning and hypothesized that only Think times would correlate with higher-level cognition in depressed and non-depressed groups. "
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ABSTRACT: Psychomotor slowing has been documented in depression. The digital Clock Drawing Test (dCDT) provides: (i) a novel technique to assess both cognitive and motor aspects of psychomotor speed within the same task and (ii) the potential to uncover subtleties of behavior not previously detected with non-digitized modes of data collection. Using digitized pen technology in 106 participants grouped by Age (younger/older) and Affect (euthymic/unmedicated depressed), we recorded cognitive and motor output by capturing how the clock is drawn rather than focusing on the final product. We divided time to completion (TTC) for Command and Copy conditions of the dCDT into metrics of percent of drawing (%Ink) versus non-drawing (%Think) time. We also obtained composite Z-scores of cognition, including attention/information processing (AIP), to explore associations of %Ink and %Think times to cognitive and motor performance. Despite equivalent TTC, %Ink and %Think Command times (Copy n.s.) were significant (AgeXAffect interaction: p=.03)-younger depressed spent a smaller proportion of time drawing relative to thinking compared to the older depressed group. Command %Think time negatively correlated with AIP in the older depressed group (r=-.46; p=.02). Copy %Think time negatively correlated with AIP in the younger depressed (r=-.47; p=.03) and older euthymic groups (r=-.51; p=.01). The dCDT differentiated aspects of psychomotor slowing in depression regardless of age, while dCDT/cognitive associates for younger adults with depression mimicked patterns of older euthymics. (JINS, 2014, 20, 1-9).
Available from: Silvia Bunge
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ABSTRACT: The ability to cognitively regulate emotional responses to aversive events is important for mental and physical health. Little is known, however, about neural bases of the cognitive control of emotion. The present study employed functional magnetic resonance imaging to examine the neural systems used to reappraise highly negative scenes in unemotional terms. Reappraisal of highly negative scenes reduced subjective experience of negative affect. Neural correlates of reappraisal were increased activation of the lateral and medial prefrontal regions and decreased activation of the amygdala and medial orbito-frontal cortex. These findings support the hypothesis that prefrontal cortex is involved in constructing reappraisal strategies that can modulate activity in multiple emotion-processing systems.
Available from: Maria Salvina Signorelli
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ABSTRACT: BACKGROUND: Depression is common in the elderly and in the last few years this led to a significant increase in antidepressant prescription rates. However, little is known about antidepressant efficacy profile in relation with socio-demographic and clinical features in this population. The aim of the present study was to define the most suitable socio-demographic and clinical profile for the use of antidepressant treatments in late-life depression. METHODS: MEDLINE, EMBASE and PsycINFO were searched for randomized controlled trials (RCTs) focused on efficacy of antidepressants of all classes in major depressed elderly subjects (>60 years old). Reviews and meta-analyses focusing on this topic have been considered as well. Thirty-four RCTs were included and socio-demographic and clinical features were investigated via meta-regression analysis as moderators of efficacy measures (standardized mean difference based on Hamilton Depressive Rating Scale and Montgomery-Asberg Depression Rating Scale). RESULTS: A lower rate of response to antidepressants of all classes was found in patients of male gender, of older age, and with a longer mean duration of the current episode. On the contrary, a higher rate of response was found in patients with a higher baseline severity and at their first episode of illness. Subsamples treated with selective serotonin reuptake inhibitors alone yielded similar results. LIMITATIONS: RCTs only have been included. CONCLUSIONS: A number of socio-demographic and clinical features have been found to moderate antidepressant efficacy in elderly population. Those variables could help clinicians for a more individualized treatment.
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