Pattern of Autism Spectrum Disorder and Co-Occurring Symptoms in Adopted Children

Background:   Adoptees have a higher risk for neurodevelopmental and behavioral problems; however there is little research on adopted children with Autism Spectrum Disorder (ASD). In the English Romanian Adoption study (Rutter et al., 2007), nearly 7% of adoptees presented with an array of autistic symptoms classified as “quasi-autism,” but this was a largely institutionalized sample that likely is not typical for the general adopted population. Looking more broadly, adoptees have an increased risk for externalizing behaviors, internalizing behaviors, and sleep problems (Juffer et al 2011).

Objectives:   To determine whether adopted children with ASD differ from the general ASD population in terms of diagnosis, internalizing and externalizing behavior, sleep problems, and medications.

Methods: We studied 163 adoptees in the Autism Speaks Autism Treatment Network (AS-ATN) in comparison to 5,624 non-adopted AS-ATN participants (age 1.5-17.6 years, M= 6.2 years, SD=3.4). Sex, age, race, ethnicity, IQ, and categorical DSM-IV ASD diagnosis were tested for differences by group (Adopted versus Non-Adopted), using independent samples t-tests for continuous variables and Fisher’s exact tests for categorical variables. Logistic regression models were used to examine the association between adoption status and several outcome variables, including co-occurring psychiatric diagnosis, Child Behavior Checklist (CBCL) internalizing and externalizing behavior problems, sleep problems, and medications after controlling for covariates. 

Results: The adopted population had a significantly higher percentage of females (27.6%) in comparison to the controls (15.9%). Adopted children were enrolled in the AS-ATN at a significantly older age (M=7.9, SD=3.8 versus M=6.2, SD=3.4; P < 0.001). After controlling for demographics, adoptees received a diagnosis of PDD-NOS significantly more frequently than controls (p<0.001, OR=1.8, 1.3-2.5) and were diagnosed at a significantly later age (p<0.001). No single DSM-IV symptom domain was significantly different between the two populations, nor were ADOS-2 scores significantly different. The adopted population showed greater propensity for externalizing behaviors (p<0.001), internalizing behaviors (p=0.001), and sleep problems (p<0.001). Further, adoptees showed higher rates of CBCL attention problems (p<0.0001), CBCL attention deficit-hyperactivity problems (p<0.001), CBCL anxious/depressed symptoms (p<0.001), and CBCL anxiety problems (p=0.001).  Adoptees were also prescribed psychotropic medications (p<0.001) more often than the non-adoptees, including ADHD (p<0.001) and sleep medications (p<0.001).

Conclusions:   These results suggest that the population of adopted children with ASD differs from the general ASD population both with regard to diagnostic timing and severity and also with regard to co-occurring behavioral problems. Future research should evaluate the contributions of specific factors associated with adoption such as biological family history, pregnancy history, early childhood experience, and age at adoption