Phenotypic manifestations for young children with fragile X syndrome (FXS) include: anxiety, sensory processing challenges, global language and communication deficits and intellectual and developmental disabilities. Many of these symptoms can be treated with medications, including selective serotonin reuptake inhibitors (SSRIs). However to date a clinical trial has not been conducted for children under five years old. This study investigated developmental outcomes and family contexts via a randomized controlled trial of sertraline for 30 children 2-6 years old diagnosed with FXS over six months via an interdisciplinary model. Results indicated

significant effects for sertraline treatment on the Clinical Global Impressions-Improvement (CGI-I) scale with 

46% of the medication group falling in the "Very Much Improved" category compared to 0% of the placebo group. The Visual Analogue Scale (VAS) results indicated significant effects for the sertraline treatment group overall and for subcategories of symptoms falling into Hyperactivity, Impulsivity and Attention (HIA). Marginally

significant trends for global cognitive improvement were noted for the sertraline group compared to placebo as measured by the Mullen Scales of Early Learning, Early Learning Composite (ELC). Significant treatment effects were not noted on specific measures of language. Social Participation, as measured by a subscale on the Sensory Processing Measure revealed significant effects of sertraline treatment indicating improved participation in family outings including errands and parties. Complexities of daily life for families living with FXS revealed patterns consistent with the phenotypic expressions noted above with the impact to the child with FXS and overall family functioning being strongly enmeshed. Overall our research revealed promising findings for an interdisciplinary research model and trial of sertraline for young children with FXS.