Bautista, Ana B.Ruiz Vegas, Francisco JavierSuárez Falcón, Juan Carlos2024-05-202024-05-2020232212-1447http://doi.org/doi.org/10.1016/j.jcbs.2023.06.004 Lhttps://hdl.handle.net/20.500.14468/12606Developing and testing psychological interventions for primary caregivers of children with cancer at significant psychosocial risk is still needed. One psychological factor contributing to their emotional distress is repetitive negative thinking (RNT). This study conducted a randomized, multiple-baseline evaluation of the effect of an individual, online, 2-session, RNT-focused ACT intervention in 12 parents. Participants responded to daily measures of emotional symptoms, RNT, and progress in values during baseline, intervention, and the 2-month follow-up. These measures have shown adequate psychometric properties at the individual level in this study. All 12 participants completed the intervention. A Bayesian hierarchical model indicated that most participants showed reductions in emotional symptoms and RNT (10 of 11), and 8 of 12 participants showed increases in valued living. The design-comparable standardized mean difference was computed to estimate the intervention effect overall. The effect sizes were large for all variables (PHQ-4: d = 0.83, 95% CI [0.27, 1.40]; RNTQ-3: d = 0.81, 95% CI [0.34, 1.28]; VQ-3: d = 1.07, 95% CI [0.22, 1.91]). Participants evaluated the intervention as useful at the 2-month follow-up. In conclusion, a brief and online RNT-focused intervention showed promising results in parents of children with cancer at significant psychosocial risk.eninfo:eu-repo/semantics/closedAccessjournal articleAcceptance and commitment therapyRepetitive negative thinkingChildhood cancerParentsSingle-case experimental designPsychosocial risk