Discussion
depression, mild-to-moderate depression, anxiety, depressive disorders
PROLIFERATION, ADVERSE EVENTS
A virtual voice-based coach intervention showed meaningful changes in a subset of select neural targets, with a decrease in the activation of the primary neural target related to cognitive control—the right dlPFC—in the intervention group compared with the control. Related self-reported rational problem-solving and impulsive/carelessness scores also showed meaningful improvements with Lumen. The change in the right dlPFC activation was also correlated positively with self-reported problem-solving ability scores and negatively with the avoidance scores in the Lumen group. Moreover, participants in the Lumen intervention group showed improvements in both depression and anxiety symptoms as well as total psychological distress at 16 weeks, compared with the waitlist control group. The between-group differences in the HADS-D and HADS-A scores were consistently greater than clinically important differences defined as 1.5–1.7 in prior studies [To the best of our knowledge, this is the first clinical trial of a virtual voice-based coach for behavioral therapy, coupled with neuroimaging, that was delivered using a consumer-based voice platform (i.e., Amazon’s Alexa). The demonstration of neural target engagement for cognitive control and improved clinical outcomes is promising and offers considerable opportunity for delivering PST. Moreover, more than 80% of the Lumen participants completed all 8 PST sessions, suggesting high feasibility and acceptability among a highly diverse group of participants.The neural mechanistic findings supplement the validated self-report clinical outcomes, and may help elucidate the theory-based therapeutic underpinnings of this novel form of PST delivery. Meaningful decrease in the activation of right dlPFC in the Lumen group is consistent with other studies suggesting that right hemisphere hyperactivation is associated with depressive disorders [The presence of moderators in our models suggests that women, minorities, those college or less educated or those with lower digital health literacy may likely benefit more from using Lumen. Among marginalized groups with lower resources and limited access to mental health services, Lumen offers a potential resource for easy and on-demand access. This is especially the case, given the significant proliferation of mobile phones with voice applications. A recent qualitative study [There is considerable published literature and on-going research on the use of text-based applications (“chatbots”) for mental health support [This study has several limitations. First, this was a pilot RCT with a small study sample, among those with mild-to-moderate depression and/or anxiety, increasing the probability of false discovery and failure to detect uncommon problems or adverse events. Nonetheless, this study provides the foundational evidence for a planned confirmatory study (NCT05603923). Second, task-based neuroimaging studies have had varying within-subjects reliability, which may have reduced the capacity to detect changes in certain neural targets. Future studies will also complement data-driven approaches such as whole-brain network analysis. Third, the comparison group did not receive any treatment, and it remains unclear how Lumen differs from PST delivered by human coaches. Fourth, we considered several moderator variables in our analysis; given the small sample size the findings should be considered preliminary. Finally, although education and digital literacy were moderating variables, the overall sample was well-educated and digitally literate.In summary, this pilot RCT provides preliminary evidence that a virtual voice-based coach may represent an alternative option of PST delivery for managing mild-to-moderate depression and anxiety. This innovative approach may reduce barriers to mental health care access, particularly for vulnerable populations.