Acceptance and commitment therapy focused on repetitive negative thinking for complicated breakup grief: A randomized multiple-baseline evaluation

Romantic relationship breakups often cause important behavioral and emotional consequences that can lead to experiencing complicated grief. However, little empirical research has tested psychological interventions for this frequent problem. This preliminary study explored the efficacy of a three-session protocol of Acceptance and Commitment Therapy (ACT) focused on repetitive negative thinking (RNT) for the treatment of complicated breakup grief in three women. A nonconcurrent, across participant, randomized multiple-baseline design was conducted. The three participants showed very large decreases in breakup distress that surpassed the criteria for claiming clinically significant changes. Two participants showed clinically significant changes in emotional symptoms, and all of them attained significant changes in life satisfaction. All three participants showed clinically significant changes in repetitive negative thinking, experiential avoidance, cognitive fusion, and valued living. Effect sizes comparable across designs were very large and statistically significant for breakup distress (d = 7.11), emotional symptoms (d = 2.46), and life satisfaction (d = 1.25). In conclusion, RNT-focused ACT protocols might be efficacious in cases of complicated breakup grief.