Five-Year Follow-up of Preschoolers with Autism and Comorbid Psychiatric Disorders

Background: Studies have reported the prevalence of total comorbid psychiatric disorders in children with autism spectrum disorders (ASD) to be from 30-80%. Such comorbid conditions are thought to not only exacerbate the social, communicative and behavioral difficulties already inherent in children with autism but also to complicate diagnosis and access to services. Despite these concerns there are no current longitudinal studies of such children regarding the impact of comorbidity.

Objectives: To assess the nature and occurrence of comorbid psychiatric symptoms in children with ASD 5.5 years after their initial diagnosis and treatment in preschool. The study focuses on the nature and extent of psychotropic medications, special education and related behavioral or mental health services potentially warranted by comorbid disorders.

 Methods:  One hundred and seventy five participants with a confirmed autism diagnosis were assessed at entry to an early intervention program (time 1). Comorbid symptoms were assessed using the Early Childhood Inventory (ECI) - 4: Parent Checklist and Child Behavior Checklist (CBCL). The Mullen and Wechsler Primary Preschool Scales of Intelligence-III (WPPSI) were used to assess intellectual functioning and to derive a mental age for each child. After 5.5 years (time 2), 44 preschoolers were located and reassessed for comorbid disorders at an average chronological age of 10 years 3 months. Comorbid symptoms were re-assessed using the Child or Adolescent Symptom Inventory - 4: Parent Checklist and the Child Behavior Checklist. A subsample of 25 families was interviewed regarding their child’s current special education programs and the types of behavioral or mental health services they were currently receiving. Careful analyses were used throughout to ensure the representativeness of the samples.

Results: Comorbidity persists in similar patterns five years after initial symptoms with the time 1 ranking as follows: ADHD, depression, dysthymia, anxiety; and the time 2 ranking as: dysthymia, ADHD, depression, anxiety. Preschool mental age predicts both mood and anxiety disorders. By around 5^thgrade, 64% were in regular class (1/3 with aides). Related services (hours/week) were: behavioral aide (17), social skills (1.5), speech therapy (1.5), and mental health services (0.3). Psychotropic medications were used by 73% of children at time 1 and 61% at time 2. Externalizing symptoms improved more than internalizing symptoms.  

Conclusions: Findings not only suggest continued comorbidity but also somewhat higher than expected use of behavioral services, often requiring out of school funding. Dysthymia was the only disorder that significantly worsened over time suggesting that identification of and treatment of at least some comorbid internalizing disorders may be sorely lacking in school settings for children with ASD.  Hours per week devoted to behavioral aides and primacy of medication for ADHD or disruptive behavior contrasted sharply with services such as counseling or related mental health services that might be more likely to target internalizing problems. Comorbid externalizing disorders, such as ADHD, seemed to fare a little better, possibly because special education and related services tend to focus on externalizing disorders.