Effects of Booster Sessions on Depression Vulnerability Following Cognitive Control Training

Cognitive impairments are closely associated with depression and recent studies have found that these cognitive problems can persist following remission of depression. Internet-delivered cognitive control training (CCT), and the adaptive Paced Auditory Serial Addition Task (aPASAT) in particular, has shown to be an effective preventative intervention for remitted depressed individuals (RMD), where beneficial effects have been found for rumination, depressive symptomatology (Hoorelbeke \& Koster, 2017), and risk for recurrence of depression (Hoorelbeke et al., 2021). At the same time, prior studies suggest significant heterogeneity in response to CCT, where RMD individuals can show strong fluctuations in functioning in the months following completion of aPASAT training. In line with this, recent findings suggest that, for individuals with high-risk profiles, initial training gains may diminish over time, resulting in recurrence of internalizing symptomatology (Hoorelbeke et al., 2022). As such, there may be merit in the use of CCT booster sessions. Currently, it is unclear whether offering additional CCT sessions when RMD individuals are reporting increased symptomatology (i.e., adding booster sessions based on early warning signs for possible recurrence of depression) can increase the long-term effectiveness of CCT. In this study, two groups of RMD individuals will perform 10 CCT sessions, after which one group will be offered booster sessions (contingent on indicators of functioning). For this purpose, we will rely on 15 weekly mobile assessments, using the PHQ-9 questionnaire. In addition, functioning will be assessed using a more extensive assessment battery at baseline, post-training (2 weeks after baseline) and follow-up (15 weeks after baseline).