Abstract | Summary | Original Article

ASDs and Attention Deficit Hyperactivity Disorder: Treatment with Stimulants

The behaviour of children with autism spectrum disorders (sometimes called Pervasive Developmental Disorders – PDD) is characterized by the “triad of impairments,” that is, problems relating to or understanding people or social situations, problems developing any means of communication, and the inability to engage in imaginative activities, substituting instead, repetitive behaviour and a resistance to change. These behaviours, while variable in their expression in individual children, are diagnostic of autism spectrum disorders when they exist as a cluster and persist over time.

A subgroup of children with autism spectrum disorders (ASD) also show signs of high activity levels, poor impulse control, and inability to pay attention. These are not considered to be symptoms of autism. They are, however, symptoms of attention deficit hyperactivity disorder (ADHD). According to the DSM-IV, the manual that describes the sets of symptoms used to make psychiatric or behavioural diagnoses, ADHD is a diagnosis that should be considered if a child does not meet the criteria for a diagnosis of Pervasive Developmental Disorder (the term used in the DSM-IV).

Over the past few years researchers have suggested that some children, instead of having one or the other condition, may have both. In one study (Frazier et al. 2001) the symptoms of ADHD in children with PDD were essentially the same as the symptoms of ADHD in children without a PDD. Children with a primary diagnosis of ADHD did not have symptoms of PDD. Taken together, these findings suggest that the conditions are distinct. A recent study by Goldstein and Schwebach (2004) showed that a group of children they studied had sufficient symptoms to warrant diagnosis of both PDD and ADHD. These authors caution that in a child or adolescent who has symptoms of both autism and ADHD, and especially the symptoms termed “social learning disability” and “impaired self-control,” life can be much more problematic for the individual and for those in contact with him or her, making treatment especially important.

Attention Deficit Hyperactivity Disorder has been treated for many years with stimulant drugs such as methylphenidate (Ritalin™) and dextroamphetamine (Dexedrine™). Studies of methylphenidate have shown a good response to the drug, with the symptoms of ADHD reduced. In the past, though, children with autism have never been treated with stimulants. One study of children with PDD and symptoms of ADHD also found that stimulant use reduced the symptoms of ADHD, but also decreased the stereotypies and inappropriate speech seen in the children (Handen et al. 2000). However, there appears to be an increased likelihood of children developing side effects such as social withdrawal and irritability, which can be severe. Researchers in Italy found that a single dose of methylphenidate could predict response to and tolerability of the drug. Children whose behaviour improved within an hour of a single dose could be classified as responders. If there was no response during that time period, the children would not respond to the drug over the long term. The authors suggest that children who have side effects within 1 hour should not be given further doses (DiMartino et al. 2004).

This evidence, although from small studies, suggests that the symptoms of autism and ADHD can coexist, whatever their relationship to each other. Treating the ADHD, which is known to respond to stimulants, may produce improvements in behaviour and thus in quality of life for children and adolescents with symptoms of both ASD and ADHD and their families.

References

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Di Martino, Melis G, Cianchetti C, Zuddas A.Methylphenidate for pervasive developmental disorders: Safety and efficacy of acute single dose test and ongoing therapy: An open-pilot study. Journal of Child and Adolescent Psychopharmacology. 2004; 14(2): 207-218.

Goldstein S, Schwebach AJ. The comorbidity of pervasive developmental disorder and attention deficit hyperactivity disorder: Results of a retrospective chart review. Journal of Autism and Developmental Disorders. 2004; 34(3): 329-339.

Handen BL, Johnson CR, Lubetsky M.Efficacy of methylphenidate among children with autism and symptoms of attention-deficit hyperactivity disorder. Journal of Autism and Developmental Disorders. 2000; 30(3): 245-255.