A randomized controlled trial of an internet-based therapist-assisted indicated preventive intervention for prolonged grief disorder

•Healthy Experiences After Loss is a web-based prevention for prolonged grief.•We examined efficacy, acceptability, and impact of professional oversight.•84 Patients with early prolonged grief entered the wait-list controlled pilot trial.•HEAL led to large reductions in prolonged grief and lower incidence rates.•Satisfaction and usability were high and professional oversight very low.

This trial assessed the feasibility, acceptability, tolerability, and efficacy of an Internet-based therapist-assisted cognitive-behavioral indicated prevention intervention for prolonged grief disorder (PGD) called Healthy Experiences After Loss (HEAL). Eighty-four bereaved individuals at risk for PGD were randomized to either an immediate treatment group (n = 41) or a waitlist control group (n = 43). Assessments were conducted at four time-points: prior to the wait-interval (for the waitlist group), pre-intervention, post-intervention, 6 weeks later, and 3 months later (for the immediate group only). Intent-to-treat analyses indicated that HEAL was associated with large reductions in prolonged grief (d = 1.10), depression (d = .71), anxiety (d = .51), and posttraumatic stress (d = .91). Also, significantly fewer participants in the immediate group met PGD criteria post-intervention than in the waitlist group. Pooled data from both groups also yielded significant reductions and large effect sizes in PGD symptom severity at each follow-up assessment. The intervention required minimal professional oversight and ratings of satisfaction with treatment and usability of the Internet interface were high. HEAL has the potential to be an effective, well-tolerated tool to reduce the burden of significant pre-clinical PGD. Further research is needed to refine HEAL and to assess its efficacy and mechanisms of action in a large-scale trial.