Experimental Design
We will implement a pilot RCT to provide evidence regarding the effectiveness of SH+, a transdiagnostic short course of group therapy for people with psychological distress, in our context. We will screen adult women for psychological distress using the PHQ-4 scale.
We will implement a RCT to obtain evidence about the effectiveness of this intervention in terms of improving mental health.
We will identify 40 locality clusters within a peri-urban area near Bangalore, Karnataka. We will randomize these clusters into three arms based on treatment status and the targeted size of the SH+ groups.
Within the forty clusters, we will randomize 10 to be “large” treatment clusters, 15 to be “small” treatment clusters, and 15 to be small control clusters. To improve power and simplify recruitment, this trial will only include women. Within the large clusters, we will seek to recruit 45 participants by screening 300 women. Within the small clusters, we will seek to recruit 20 participants by screening 135 women. We assume that 67 percent of participants will join the SH+ groups, so that the large clusters will have around 30 people per group and the small clusters will have around 13 people per group. Under this approach, we will screen 7000 women to obtain a sample of 1050 study participants. Using an “intent to treat” approach, we will measure effects among all individuals who we recruit, regardless of whether they actively participate.
The comparison of the small treatment and control clusters allows us to assess whether the intervention is effective relative to a pure control group. The comparison of the large treatment clusters and the small treatment clusters allows us to measure the differential impact for larger clusters, which is a key piece of evidence that informs the scalability and cost effectiveness of this intervention.
To assess final outcomes, we will carry out a baseline and two follow-up surveys. The baseline survey will occur at the time of recruitment. It will collect key demographic variables and mental health outcomes that will serve as the primary outcomes for our analysis. The first follow-up survey will occur after the conclusion of the five-week SH+ course. This survey will measure the baseline outcomes again, as well as relevant behavioral and socioeconomic outcomes.
The second follow-up survey is intended to give preliminary evidence regarding the effectiveness of SH+ over a longer time frame. A few months after the baseline survey, we will offer an SH+ booster session in the small treatment clusters. Afterward, we will implement the second follow-up in these clusters. This approach will provide an indication about whether effects diminish over time and whether a booster session increases the longevity of the intervention impacts.