Enhancing depression treatment: Development and (cost-)effectiveness of a digital add-on alcohol intervention for young adults with co-occurring depression and problematic alcohol use

Depression and problematic alcohol use frequently co-occur among young adults. This co-occurrence is associated with various negative health outcomes. A tailored digital add-on alcohol self-help which can be followed alongside the depression treatment may be a suitable and effective intervention for young adults with these co-occurring conditions. However, the evidence base on the (cost-)effectiveness of digital interventions for young adults with these co-occurring depression and problematic alcohol use is currently insufficient. In Chapter 2 we examined whether non-drinking, at-risk and high risk drinking was associated with depression persistence after a 3-year follow-up among adults with MDD from the Dutch general population. Using NEMESIS-2 data (n = 642), we found no statistically significant association between alcohol use and MDD persistence. Chapter 3 reported on a systematic review with meta-analysis in which we assessed the effectiveness of digital interventions among people with co-occurring depression and problematic alcohol use. We conclude that digital interventions are effective in reducing depressive symptoms at 3-month follow-up and possibly alcohol use at 6-month follow-up among people with comorbid depression and problematic alcohol use. In Chapter 4, we presented the study protocol of our RCT in which we aimed to evaluate the (cost-)effectiveness of a digital add-on alcohol intervention (Beating the Booze, BtB) for young adults (18-35 years) in depression treatment. BtB is a web-app designed as a CBT/MI-based modular self-help, developed to be followed simultaneously but not integrated with regular depression treatment (treatment as usual, TAU) and included minimal adherence-focused guidance from a coach. Participants were randomized to either the experimental (BtB + TAU) or the control group (TAU only). Self-report follow-up assessments took place at 3, 6 and 12 months post-randomization. The primary outcome was treatment response at 6-months follow-up. An economic evaluation was conducted alongside the trial. In Chapter 5 we presented the results of our qualitative study, in which we conducted focus groups in order to explore the preferences of young adults (n = 29) regarding the content, design and features of the digital alcohol intervention. Findings indicated that young adults preferred a mobile health application with a clear and simple objective and navigation, which was also accessible on a computer. Participants indicated a preference for in-depth, gain-framed information on alcohol use and a main feature enabling them to record their alcohol use and mood. Other preferences included (but not limited to) personal goal-setting and monitoring, an activity list, experience stories, peer contact, guidance from experts by experience and receiving notifications. Regarding the design, young adults preferred short, animated videos and animation figure illustrations to complement written text. In Chapter 6 we reported findings of our RCT (n = 163), in which we examined the treatment effects of BtB + TAU compared to TAU alone after 3- and 6-months follow-up among young adults with co-occurring depression and problematic alcohol use. We concluded that the digital add-on alcohol intervention was effective in reducing alcohol use outcomes, but not for treatment response and depression outcomes among young adults with co-occurring depression and problematic alcohol use. In Chapter 7 we presented the findings of our economic evaluation, in which we examined the 12-months treatment effects, cost-utility and cost-effectiveness of our digital add-on alcohol intervention for depression treatment (BtB + TAU) compared to TAU only among young adults. We concluded that by adding the digital alcohol intervention to depression treatment, young clients are likely to benefit from improvements on alcohol and quality of life related outcomes, while this add-on likely offers good value for money for society as a whole. It can therefore be recommended to further explore potential implementation opportunities for the digital add-on alcohol intervention.