Major depressive disorder (MDD) is characterized by reduced activation of the dorsolateral prefrontal cortex (DLPFC), a brain region involved in both emotion regulation and basic cognitive control processes. Recent studies have indicated that computerized interventions designed to activate the DLPFC can reduce depressive symptoms. The current study was a randomized controlled trial which extends this research to test whether one such program, called Cognitive Control Training (CCT), enhances depression treatment outcomes when used in adjunct to brief behavioral activation therapy for depression (BATD), an empirically-supported outpatient intervention. This study also explored whether the effects of BATD + CCT treatment on depression were mediated by changes in rumination and cognitive control. In a sample of thirty-four adults diagnosed with MDD, participants were randomly assigned to complete four sessions of either computerized CCT or a non-active computerized control task, concurrently with four sessions of BATD. Completion of the assigned computerized task took place immediately before each of the four BATD therapy sessions. Depression symptoms and proposed treatment mediators were assessed at baseline, mid-treatment, post-treatment, and four-week follow-up visits. I hypothesized that compared to the control group, participants receiving adjunctive CCT would demonstrate significantly reduced depressive symptoms. I also hypothesized that these effects would be mediated by changes in inhibitory control and set-shifting performance in the context of negative emotional material, as well as by changes in ruminative brooding. Results did not support these hypotheses. Depressive symptoms were reduced over time in both treatment conditions, with no significant difference between treatment conditions. Assignment to CCT was not associated with changes in the proposed mediators. Furthermore, exploratory analyses found minimal evidence that performance on inhibitory control and set-shifting tasks were related to baseline clinical characteristics (such as depression severity, rumination, or anxiety symptoms) or treatment outcomes. The results of this study support the potential for BATD as a brief, low-cost, flexible intervention for the treatment of depression and further show that CCT administered in adjunct to a 4-session BATD program does not add clinical benefit in the treatment of depression. This study and other recent research suggest that the effects of CCT may not be as robust as previously indicated, highlighting the need for continued investigation of the conditions under which CCT may be effective.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/14051 |
| Date | 28 November 2015 |
| Creators | Moshier, Samantha J. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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