Research paper · RP43

Single Session, Lasting Change?

Schleider and Weisz showed that one sitting can help young people. This review asks the adult question: how much does one sitting buy, and for how long? Across adult randomised and controlled trials of single-session or 15-minute-or-shorter practices published from 2010 to 2026, a single sitting produced a small follow-up effect of g = 0.15 (95% CI 0.05 to 0.22) on distress or wellbeing at four to eight weeks; most 10-minute digital programmes did not outlast the month. A conservative all-comers pool that kept the null digital programmes in the average found g = 0.08 (95% CI 0.00 to 0.16). Immediate state hope, gratitude and agency moved more, with a short-horizon pooled estimate near g = 0.48 (95% CI 0.18 to 0.79), but those lifts were often gone by four weeks. The largest adult trial assigned 7,505 people with elevated low mood to one of twelve 10-minute digital programmes or a no-content control; only two programmes still beat control on depression at four weeks (d = 0.14 and 0.15). Longer scripts were not better. An 8-minute loneliness practice outperformed a 23-minute version of the same material at eight weeks (d = 0.22). Heterogeneity at follow-up was low once the megastudy dominated the weights. Small live-session trials against waitlists produced larger effects and higher risk of bias. Egger’s test in mixed pools suggested small-study inflation. Certainty is moderate for same-day state change and low-to-moderate for follow-up. No eligible adult trial was conducted in India. One sitting is a first countable rep, not a course. For Indian workplaces the number is useful precisely because it is small and honest: a 10-minute WhatsApp-first practice can open a door. It does not replace a human hand-off.