SST Research

Single-session interventions have a robust evidence base.

Single-session approaches to addressing mental health problems are not new. Reports of meaningful improvements from one-session clinical encounters have been documented across psychotherapy’s history, and empirical evaluations of single-session approaches date back to the 1980s. However, interest in single-sessions from clinicians, researchers, and implementers has surged in the past decade, reflecting widely-felt needs for innovative approaches to delivering and scaling-up effective mental health supports.

Single-session interventions are broadly defined as “structured programs that intentionally involve only one visit or encounter with a clinic, provider, or program” (Schleider et al. 2020). Single-session interventions have gone by many names, including “single-session therapy,” which are single-sessions delivered by a mental health professional; “One-Session Treatment”, referring to a specific treatment for specific phobias; and “one-at-a-time therapy”, where each therapist-delivered session is meant to stand on its own, with no assumed treatment duration.

We (the Lab for Scalable Mental Health) use “single-session interventions” as an umbrella term that is maximally inclusive as to what one-session supports can look like (e.g., online programs or in-person supports) and how they can be delivered (i.e., by trained therapists, lay health workers, or as self-guided interventions with no provider).

Regardless of their format or delivery modality, single-session approaches are intended to be an as-needed approach to treatment. They may be completed once, on multiple occasions, or as adjuncts to intentionally longer-term care. There is no assumption within the single-session framework that individuals always can or should address all their concerns within one session; rather, these supports are designed such that any one session holds potential to yield some degree of positive, meaningful change. That is, single-sessions acknowledge the dual realities that any given clinical encounter could be someone’s last (whether or not they want or might benefit from additional support), and that any single-session can nonetheless yield meaningful benefit (in the form of symptom reductions, increased support-seeking, or both).

To date, there have been at least 415 clinical trials of single-session interventions for mental health problems in children, adolescents, and adults. Together, they show that single-session approaches are effective for multiple problems and age-groups. Our lab’s new umbrella review, to appear in the Annual Review of Clinical Psychology (2025), reports on the state of the science to date.

More research and readings on single-session approaches: