Longitudinal Analysis of Children Referred for ASD Evaluation: Exploring Outcomes for Individuals Without Confirmed ASD Diagnoses.

Diagnosing autism spectrum disorder (ASD) is complex due to overlapping conditions and frequent comorbidities. This study aimed to explore the clinical and developmental outcomes of children referred for ASD evaluation but not diagnosed with ASD, describing the long-term diagnostic and treatment patterns in this population. We conducted a retrospective cohort study of 37 children (aged 1-13 years) evaluated for ASD at a regional clinic between 2011 and 2017 but not diagnosed with ASD (non-ASD group). A control group of 32 children consecutively diagnosed with ASD during the same period was included. Electronic medical records of both groups were reviewed 2-9 years post-assessment, focusing on diagnostic changes, service utilization, and treatment patterns. Both groups exhibited significant impairments and high service utilization at follow-up. ADHD was commonly diagnosed in both groups, while specific learning disorders (SLD) were more prevalent in the non-ASD group. Notably, approximately 20% of children in the non-ASD group received an ASD diagnosis at follow-up. Most children received psychopharmacological treatment, with stimulants being the most prescribed. Combination treatments were less common in the non-ASD group. Children referred for ASD evaluation but not initially diagnosed with ASD often experience substantial impairments and comorbidities, particularly ADHD and SLD. They require ongoing, multifaceted care. These findings underscore the need for long-term monitoring and tailored interventions for this population.