A study just published in the journal Research in Autism Spectrum Disorders found that a staggering 53% of over 1500 autistic subjects (aged 2 to 17) exhibited aggressive behaviors. We asked the lead author, Dr. Micah O. Mazurek, to explain the significance of his data.
EASI: Does the fact that close to 50% of the subjects across all age groups exhibit aggressive behaviors suggest to you that these behaviors persist over time - i.e., that it's likely that aggressive autistic children will grow into aggressive autistic adults?
Dr. Mazurek: Yes, I agree that these percentages across time (particularly among older adolescents) are quite alarming. The effects of aggression can be more serious as individuals reach adolescence and adulthood, so we think this finding is certainly concerning. I would like to mention, though, that this was a cross-sectional study. We weren't able to follow the same individuals over time to determine the long-term course of aggression for an individual child. It is also important to note that our measure of aggression was very broad, so it is likely that the severity ranged from mild to more severe (among children who were classified as having aggression).
EASI: Considering these subjects are all part of the Autism Treatment Network, is it fair to assume all the children were being treated for their aggressive behaviors? Given, as mentioned above, the small decrease in aggression found in older children, would it be fair to say that current treatment protocols for aggression (behavior plans, antipsychotics, etc.) are not very effective?
Dr. Mazurek: Actually, the data for this study were collected when children were first enrolled in the ATN (their "baseline" data). For this study, we didn't collect data on treatments received prior to their enrollment, so we can't really address the question of treatment effects. Because the ATN is a longitudinal project, however, our next step in this line of research is to examine the course of aggression over time, predictors of improvement (or worsening) of aggression, and response to treatments.
EASI: What implications do your findings have for the health care system - in other words, how are we as a nation going to care for such an enormous population of aggressive, autistic adults?
Dr. Mazurek: Aggression is a serious issue - with obvious negative effects for the individual as well as his/her family and community. Not only does aggression result in physical harm, but it can lead to poor long-term outcomes (increased risk of out-of-home placement, increased use of psychotropic medication, increased family stress, caregiver/teacher burnout, etc). Aggression and other challenging behaviors also interfere with an individual's ability to participate and benefit from therapies and educational services, which also affects long-term success. For all these reasons, I think we need to be focusing much more attention on identifying underlying mechanisms of aggression in subsets of children, and developing prevention and treatments that are individualized to address those particular mechanisms.
EASI: Are you currently working on, or do you plan on working on, additional studies examining severity of or effective treatments for aggression?
Dr. Mazurek: Yes - I am very interested in continuing to pursue this research, and am hopeful that our work will provide some answers that may help families and children in the future. My colleagues and I published the results of another large-scale study of prevalence and predictors of aggression in children with ASD in 2011, and we are continuing to study the long-term course and outcomes of aggression across ages and functional levels.
We are also very interested in developing or modifying treatments to help address this issue. For example, we are in the process of completing a clinical trial examining the effectiveness of an adapted therapy for adolescents with ASD and aggression and their families. We hope to be able to share the results of this study in the near future.