Functional analysis and treatment of problem behavior exhibited by children with fragile X syndrome

•We provide functional analysis and treatment for children with fragile X syndrome.•Problem behavior is primarily maintained by access to escape and/or tangible items.•Behavioral treatment produces an 85% or greater reduction in problem behavior.•Treatment effects are successfully transferred to home and community.•Findings contribute to the functional behavioral phenotype for problem behavior. The efficacy of function-based interventions for the treatment of severe problem behavior exhibited by individuals with intellectual and developmental disabilities (IDD) is well established. However, few studies have reported on behavioral interventions in fragile X syndrome (FXS) specifically. The present study is a consecutive case-series analysis that reports on functional analysis and treatment of problem behavior of nine children with FXS. Assessment findings were consistent with previous research indicating that among individuals with FXS, problem behavior is more commonly maintained by escape from demands and access to tangible items, relative to the broader population of individuals with IDD. Functional analysis-based behavioral interventions resulted in a mean reduction in problem behavior of 95.2% across the nine participants. Additionally, generalization of treatment effects from controlled clinical settings to home, school, and community was demonstrated. The current findings suggest that function-based behavioral interventions shown to be effective with the broader population of individuals with IDD are also effective for individuals with FXS. Our results in combination with those of previous studies describing functional analysis outcomes provide additional evidence for a unique functional behavioral phenotype for severe problem behavior in individuals with FXS. Implications of study findings for early intervention and prevention of problem behavior in children with FXS are discussed.