December 2010


Understanding Aggression from Low-Functioning Autistic Children

SUMMARY: Low-functioning autistic children tend to be most violent when they are anxious or excited.
The challenges low-functioning autistic children face in communicating and socializing with others is made more difficult when they exhibit aggressive behavior, i.e. direct violence towards another person or object. Given that typical infants generally show aggression, yet learn to overcome these impulses, some scientists speculate that low-functioning autistic children have difficulties learning how to control aggressive impulses.

Identifying the situations most likely to elicit aggressive behavior from such children will help caregivers manage it. Sylvie Tordjman (Université de Rennes, France) and coworkers have carried such a study, finding that anxiety or excitement increases the risk of aggressive behaviors from autistic children.

This research is complimentary to the finding that autistic childrens' ability to recognize an object depends upon its shadow, probably a consequence of autistics' tendency to see detail more readily than other people, with possible implications in understanding why autistic people have difficulties interpreting facial cues.

The children.

The scientists studied 74 French children (25 females) with autism (by standard diagnostic criteria), on average 12 years old, with an average IQ of 42. Forty-nine of the children appeared to lack verbal language.

These children were compared and contrasted with 115 typically-developing French children (40 females), on average 13 years old. "Typical" in this case is defined as being free of psychological, developmental, or neurological disorders (as determined by two independent pediatricians), and no autism among their parents or siblings.

All of the children were Caucasian. None of the typical children were on medication, while 26 of the 74 autistic children were on medication (e.g. anticonvulsants for epilepsy).

Aggressive behavior.

The childrens' aggressive behavior was measured according to the Other-Injurious Behavior Scale, shown by other scientists to reliably measure aggression among autistic individuals. Briefly, such behavior was measured on a 1-7 scale for 15 types of behavior (e.g. slapping, tearing, and biting).

These behavioral assessments of the autistic children were conducted for three different situations (daycare, home, and during a blood drawing). Typical children were given a similar assessment.

Care was taken to minimize stress during the blood drawing. The childrens' parents were present, no white (medical) coats were worn during the procedure, the children were allowed to play for 15 minutes prior to the blood drawing, and it was performed by a nurse with notable experience with handicapped children.

When are autistic children most violent?

No association of either gender, IQ, age, medication, or physical development status was found with aggressive behavior among the autistic children. Thus, any such enhanced behavior is likely to be associated with autism.

Particularly notable aggression included slapping, pinching, and object scattering. Anxiety and excitation were the behaviors most likely to proceed aggression, most frequently accompanied by frustration, anger, and opposition.

The caregivers and parents often gave different quantitative ratings (parents were less likely to note aggression). However, the qualitative trends held for both groups of evaluators.

Also of note is that 23% of the autistic children exhibited aggression (biting, slapping, and pinching) during the blood drawing. None of the typical children did so, even if they expressed verbal or nonverbal fear.

Study limitations and prospects.

This research does not preclude the possibility that mental retardation or a lack of verbal development is responsible for increased aggression in low-functioning autistic children, rather than autism per se. Further studies are needed to answer these questions.

These finding are nevertheless useful for predicting the situations likely to provoke aggressive behavior among low-functioning autistic children (anxiety and excitation). Perhaps such environmental circumstances should be minimized in relevant care centers.

NOTE: The scientists' research was funded by the National Scientific Institute of Medical Research.
Bronsard, G., Botbol, M., & Tordjman, S. (2010). Aggression in Low Functioning Children and Adolescents with Autistic Disorder PLoS ONE, 5 (12) DOI: 10.1371/journal.pone.0014358