Demonstration of a "leapfrog" randomized controlled trial as a method to accelerate the development and optimization of psychological interventions

$\bf Background$ The scale of the global mental health burden indicates the inadequacy not only of current treatment options, but also the pace of the standard treatment development process. The "leapfrog" trial design is a newly-developed simple Bayesian adaptive trial design with potential to accelerate treatment development. A first leapfrog trial was conducted to provide a demonstration and test feasibility, applying the method to a low-intensity internet-delivered intervention targeting anhedonia. $\bf Methods$ At the start of this online, single-blind leapfrog trial, participants self-reporting depression were randomized to an initial control arm comprising four weeks of weekly questionnaires, or one of two versions of a four-week cognitive training intervention, imagery cognitive bias modification (imagery CBM). Intervention arms were compared to control on an ongoing basis via sequential Bayesian analyses, based on a primary outcome of anhedonia at post-intervention. Results were used to eliminate and replace arms, or to promote them to become the control condition based on pre-specified Bayes factor and sample size thresholds. Two further intervention arms (variants of imagery CBM) were added into the trial as it progressed. $\bf Results$ $\it N$ = 188 participants were randomized across the five trial arms. The leapfrog methodology was successfully implemented to identify a "winning" version of the imagery CBM, i.e. the version most successful in reducing anhedonia, following sequential elimination of the other arms. $\bf Conclusions$ The study demonstrates feasibility of the leapfrog design and provides a foundation for its adoption as a method to accelerate treatment development in mental health. Registration: clinicaltrials.gov, NCT04791137

Loving-kindness meditation promotes mental health in university students

$\bf Objectives:$ Loving-kindness meditation (LKM) has been shown to improve wellbeing and positive emotions in clinical and non-clinical populations. The main goal of the present study was to examine whether LKM might be an effective intervention to promote positive mental health using the Positive Mental Health Scale (PMH) and to decrease depression, anxiety, and stress in university students. $\bf Methods:$ The sample ($\it n$ = 110) consisted of university students in Germany. One half of them ($\it n$ = 55) underwent LKM intervention. They were compared with a matched control group ($\it n$ = 55) which did not receive treatment. All participants completed positive and negative mental health measures at baseline and 1-year follow-up assessments. LKM participants additionally completed the same measures before and after treatment. Multiple analyses of variance were conducted to test for short- and long-term effects of LKM on positive and negative mental health measures. $\bf Results:$ A significant short-term effect of LKM on anxiety and PMH was found. Long-term analyses revealed a significant decrease of depression, anxiety, and stress for LKM completers, and a significant increase of depression, anxiety, and stress for the control group. $\bf Conclusions:$ The results suggest that LKM enhances mental health in university students