Interaction between subgroup membership on responses to MT
Sixty-one participants were included in these analyses due to two participants not completing follow-up assessment surveys. To determine whether psychological phenotype significantly interacted with treatment responses to MT, a mixed measures 3-way ANOVA using TIME (baseline, 1, 2 months post-intervention) as a repeated measures factor, as well as GROUP (TAU + MT, TAU) and CLUSTER as between-subjects factors was conducted on GAD-7 scores. Follow-up analysis (within cluster GROUP X TIME mixed measures ANOVA and contrasts) were conducted to break down a TIME X GROUP X CLUSTER interaction effect, where applicable.To examine whether participants in different clusters may have exhibited different treatment responses due to reduced levels of engagement in the intervention, a TIME X CLUSTER ANOVA was conducted on engagement measures in the TAU + MT participants, for which levels of TIME included were one and two months post-intervention (since no module had been completed at baseline). These data analyses are described in fuller detail in the Supplementary Materials section.