Autism and attachment disorder symptoms in the general population: Prevalence, overlap, and burden.

Background: Co-occurring trauma-related and neurodevelopmental problems are common in maltreated children. In population research and clinical practice, these tend to be considered separately. Overlapping health problems, that is, "multi-morbidity," in adulthood is associated with increased service burden and costs, but this has not been investigated in childhood. Methods: Using well-validated parent-report questionnaires, we examined the overlap between symptoms of the neurodevelopmental disorder autism (autism spectrum disorder, ASD) and symptoms of the trauma- and stressor-related disorders (reactive attachment disorder [RAD] and disinhibited social engagement disorder [DSED]) in a representative general population sample of over 3,300 children aged 5-6 years of age. We investigated sociodemographic factors, service burden, and costs in association with these problems when considered separately and when co-occurring. Results: Nearly 2% of this population had symptoms suggestive of both ASD and RAD/DSED. High symptom scores for ASD were associated with male gender, (younger) age of mother at birth, and being in a single-parent family, while high symptom scores for RAD/DSED were associated with (younger) age of mother at birth, being in a single-parent family, and the number of accidents reported. Service use costs per likely case of both ASD and RAD/DSED in the preschool years were increased by £348.62 (95% confidence interval 121.04-391.11)-nearly double the costs of ASD alone. Conclusions: There is considerable overlap between symptoms of ASD and RAD/DSED in the general population, indicating that multi-morbidity is already present in childhood and is associated with increased service use and costs even in the preschool years.