Discussion
depression, present-mindedness, anxiety
RECRUITMENT
Results showed that a 2-week MEMI versus SMP led to a significantly greater increase in state mindfulness and greater reductions in state anxiety and state depression pre- to posttreatment. Simultaneously, MEMI was significantly better than SMP in decreasing GAD severity and repetitive negative thinking and enhancing trait mindfulness at pre-1MFU, but there was no differential treatment efficacy on these measures at pre–post treatment. We also found significant between-treatment effects favoring MEMI on stronger inhibition at pre- to posttreatment and pre-1MFU. Although some within-treatment significant effect sizes were moderate-to-large, the between-treatment effect sizes were generally small, signaling that any present enthusiasm surrounding brief digitally-delivered MBIs should be tempered pending further research.Our treatment effects were comparable to the small yet significant effect sizes observed in other brief app and Internet-based psychotherapy trials for GAD [Why were there substantially larger pre-1MFU than pre- to posttreatment reductions in GAD severity and perseverative cognition tendencies in MEMI than SMP? Perhaps the MEMI (versus SMP) conferred more robust improvements in observational skills and engagement in moment-to-moment awareness, acceptance, and receptivity to physical sensations, thoughts, and experiences [What are plausible change mechanisms via which MEMI outperformed SMP in reducing GAD severity, perseverative cognitions, and promoting trait mindfulness at pre-1MFU? Practicing mindfulness moment-to-moment might have enhanced present-mindedness and metacognitive skills (i.e., non-reactively observing emotions and thoughts in real-time) versus being overly preoccupied while brooding or worrying [Consistent with Some unanticipated impacts of SMP emerged during pre- to posttreatment. Whereas MEMI reduced state depression and anxiety and increased state mindfulness, SMP raised state depression and decreased state mindfulness across pre- to posttreatment. Such results were inconsistent with evidence that self-monitoring alone could positively affect worry severity [Findings need to be construed in light of the strengths and limitations herein. First, the 2-week treatment duration might be insufficient to produce more immediate improvements in trait mindfulness, GAD severity, perseverative cognitions, and inhibition; nonetheless, the findings appeared more promising for habitual worriers during pre-1MFU. Second, our study did not include measures to evaluate how MEMI participants continued practicing mindfulness skills posttreatment to 1MFU. Future studies should thus consider whether unceasing mindfulness practices, even without repeated instructions via the MEMI, might have contributed to any differential treatment efficacy at follow-up. Also, our study inferences might not generalize beyond primarily White females, highlighting the importance of future digital mental health trials to recruit a more diverse sample. In addition, despite randomization, the intervention and control groups had uneven sample sizes. Study strengths included the gold standard RCT design with active control, high compliance rate, recruitment of a well-powered clinical sample, and inclusion of a 1MFU assessment. Also, our attrition rate of 11% was lower than the average of 24 to 50% in smartphone-delivered RCTs [If our pattern of findings is replicated, some clinical implications merit consideration. Promoting the use of MEMI in treatment for GAD may bridge the chasm between the therapist’s office and chronic worriers’ everyday life. As clients continually use mindfulness skills, new helpful action repertoires and mindsets might replace old limiting habits, such as avoiding shifts from positive or neutral to negative states [