Intervention research to benefit people with autism: How old are the participants?

Abstract

We determined the reported ages of participants with autism (or autism spectrum disorders) in 146 intervention research studies published recently in four prominent journals. Most participants were between two and eight years of age and only 1.7% of them were 20 or more years of age. These findings suggest that the special needs of older people with autism have generated little interest among researchers, which is arguably an unfortunate oversight.

Introduction

Kanner (1943) called attention to autism nearly 70 years ago and since that time interest in the condition has increased exponentially. Much of this interest has involved attempts to develop systematic interventions that improve the lives of people diagnosed with the condition, and with the related conditions comprised by the broader diagnostic category of “autism spectrum disorders” (henceforth, “autism” will be used in this broader sense). Autism emerges in childhood and there is good evidence that early intervention is key to maximizing the quality of life of people with autism (e.g., Harris and Handelman, 2000, Lovaas, 1987, Sheinkopf and Siegel, 1998). Corsella (2005) clearly makes this point in a review of the relevant literature, beginning her conclusion thusly: “The available evidence from a variety of programs and studies suggests that early intervention leads to better outcomes” (p. 82). She cautions, however, that “It is important that professionals and parents are informed about the progress they can expect for their child, as well as remain aware that most research does not support a ‘cure’ or ‘recovery’ from autism” (p. 83). That being the case, it is reasonable to assume that many people with autism will have special needs, and hence potentially benefit from therapeutic interventions, throughout their lifespan.

This point was made compellingly by Shattuck et al. (2007). Those authors reported that the specific symptoms of autism and the maladaptive behaviors emitted by people diagnosed with autism changed as people aged, and typically became milder, but most individuals in their sample “remain significantly impaired and dependent on the assistance of others for daily living” (p. 1746). “Therefore,” they wrote, “our findings should give greater impetus to extending interventions and services for this population across the life course” (p. 1746). Taking a different tack, Ganz (2007) estimated the age-specific use and financial costs of nonmedical and medical care of people with autism and noted “although autism is typically thought of as a disorder of childhood, its costs can be felt well into adulthood” (p. 343). Interestingly, he estimated the average per capita cost of behavioral therapies as $32,501, $4033, $3479, and $1235 for the age groups 3–7, 8–12, 13–17, and 18–22 years, respectively, and as $0 for all older age groups. These data suggest that most adults with autism receive no behavioral therapy, even though Shattuck et al.’s findings suggest that many such individuals experience significant behavioral challenges.

Although it is apparent that much of the intervention research involving people with autism involves treatment arranged in childhood, to our knowledge no one has examined the relative number of studies that focus on people with autism in various age groups. The purpose of the present study was to provide such information for a substantial number of recent publications in four prominent autism journals.