Effectiveness of a Developmentally Attuned Exposure Therapy for Young Children with Williams Syndrome and Specific Phobias

Abstract

Williams syndrome is a rare neurogenic disorder caused by a hemizygous deletion on chromosome 7, with a prevalence of 1 in 7,500. The most common comorbid anxiety disorder among children with Williams syndrome is specific phobia (53%; Leyfer et al., 2006). Although there is some evidence for the promise of CBT approaches for people with Williams syndrome and anxiety, evidence-based interventions specifically targeting phobias in children with Williams syndrome have yet to be examined. Exposure therapy is the gold standard, well-established treatment for specific phobias in typically developing children (APA Division 12, 2017), and recent studies indicate that even a brief CBT intervention has demonstrated improvements. Our research team recently adapted and manualized a play-based exposure therapy for children with developmental disabilities and emotion dysregulation challenges (Replays) in a clinician-researcher partnership. This approach is based in the core principles of exposure therapy and uses play and humor to entice children to engage with their phobic stimulus in ways that do not overly dysregulate them. We then conducted a pilot study with a small sample of children with Williams syndrome who displayed strong emotional reactions to specific stimuli, demonstrating the promise of this intervention (Klein-Tasman et al., 2022). Building from those preliminary findings, the current study examined the effectiveness of this brief, developmentally adapted cognitive-behavioral exposure intervention for children with Williams syndrome and specific phobias. Five children aged 4-8 with Williams syndrome and co-occurring specific phobia (4 girls; 1 boy) participated, accompanied by at least one primary parent or caregiver. A non-concurrent multiple baseline across participants design was used to analyze the impact of this developmentally attuned exposure therapy on child fear and phobia-related interference across measures of clinical severity, global improvement, as well as daily and weekly parent-report ratings. Four of five children achieved remission for their primary targeted phobia by the 1-month and/or 3-month follow up timepoints, based on clinical severity ratings. These same four participants were deemed treatment responders at both the 1-month and 3-month follow up, based on clinician-rated global improvement and showed reductions in child fear and phobia-related interference on at least one metric of weekly or daily parent-report ratings. Discussion of measurement strengths and limitations in this single-case design is included, particularly related to clinical implications and future directions of this treatment development line of research. This treatment effectiveness study builds on the preliminary findings of this work (Klein-Tasman et al., 2022; Young et al., 2023), providing more confident evidence of the positive impacts of this developmentally attuned exposure therapy for young children with Williams syndrome and specific phobias using single case series design.