Cognitive Behavior Therapy vs Mindfulness in Treatment of Prolonged Grief Disorder: A Randomized Clinical Trial.

Importance: Although grief-focused cognitive behavior therapies are the most empirically supported treatment for prolonged grief disorder, many people find this treatment difficult. A viable alternative for treatment is mindfulness-based cognitive therapy.

Objective: To examine the relative efficacies of grief-focused cognitive behavior therapy and mindfulness-based cognitive therapy to reduce prolonged grief disorder severity. Design, Setting, and

Participants: A single-blind, parallel, randomized clinical trial was conducted among adults aged 18 to 70 years with prolonged grief disorder, as defined in the International Classification of Diseases , 11th Revision , and assessed by clinical interview based on the Prolonged Grief−13 (PG-13) scale. Those with severe suicidal risk, presence of psychosis, or substance dependence were excluded. Between November 2012 and November 2022, eligible participants were randomized 1:1 to eleven 90-minute sessions of grief-focused cognitive behavior therapy or mindfulness-based cognitive therapy at a traumatic stress clinic in Sydney, Australia, with follow-up through 6 months.

Interventions: Both groups received once-weekly 90-minute individual sessions for 11 weeks. Grief-focused cognitive behavior therapy comprised 5 sessions of recalling memories of the deceased, plus cognitive restructuring and planning future social and positive activities. Mindfulness-based cognitive therapy comprised mindfulness exercises adapted to tolerate grief-related distress.

Main Outcomes and Measures: The primary outcome was change in prolonged grief disorder severity measured by the PG-13 scale assessed at baseline, 1 week posttreatment, and 6 months after treatment (primary outcome time point), as well as secondary outcome measures of depression, anxiety, grief-related cognition, and quality of life.

Results: The trial included 100 participants (mean [SD] age, 47.3 [13.4] years; 87 [87.0%] female), 50 in the grief-focused cognitive behavior therapy condition and 50 in the mindfulness-based cognitive therapy condition. Linear mixed models indicated that at the 6-month assessment, participants in the grief-focused cognitive behavior therapy group showed greater reduction in PG-13 scale score relative to those in the mindfulness-based cognitive therapy group (mean difference, 7.1; 95% CI, 1.6-12.5; P = .01), with a large between-group effect size (0.8; 95% CI, 0.2-1.3). Participants in the grief-focused cognitive behavior therapy group also demonstrated greater reductions in depression as measured on the Beck Depression Inventory than those in the mindfulness-based cognitive therapy group (mean difference, 6.6; 95% CI, 0.5-12.9; P = .04) and grief-related cognition (mean difference, 14.4; 95% CI, 2.8-25.9; P = .02). There were no other significant differences between treatment groups and no reported adverse events. Conclusions and Relevance: In this study, grief-focused cognitive behavior therapy conferred more benefit for core prolonged grief disorder symptoms and associated problems 6 months after treatment than mindfulness-based cognitive therapy. Although both treatments may be considered for prolonged grief disorder, grief-focused cognitive behavior therapy might be the more effective choice, taking all factors into consideration.

Trial Registration: anzctr.org.au Identifier: ACTRN12612000307808