Contributing Factors of Aggression and Self-injury in Autism

Although self-injury and aggression are not included in the diagnostic criteria for a diagnosis of autism, they are often associated with the diagnosis (American Psychiatric Association, 2013). These symptoms are often the most problematic and concerning symptoms that caregivers face when seeking treatment for their loved ones. Best practices indicate that the first course of action is for the person to receive a thorough assessment that not only assesses specific times and activities in which the behaviors may be more severe, but the function or purpose of the behavior itself. Information from multiple respondents is typically necessary to obtain adequate information regarding the nature of the individual’s difficulties. This assessment process is called a functional behavior assessment (FBA). Once a functional behavior assessment is conducted, the results of the assessment are then used to develop a treatment plan that is individualized and specifically addresses the method in which interventions and modifications will be implemented to assist the individual in obtaining his or her needs with a more acceptable form of behavior. A second assessment option is a functional analysis (FA), which is a type of functional behavior assessment. This type of assessment is considered to be the standard in assessing problem behaviors (Hanley, Iwata, & McCord, 2003). A functional analysis is a standardized procedure, conducted in a controlled setting, in which the presentation and removal of stimuli is systematically conducted for the purpose of identifying which stimuli results in the highest proportion of problem behaviors. Once the stimuli can be identified the function of the problem behavior can be determined and a behavior intervention plan can be developed.

These methods are highly effective in identifying the function of an individuals’ self-injurious and aggressive behaviors, however, when the results are indicative of a behavior that serves multiple functions or a sensory function, treatment options may become more complicated. In these situations, an individual’s self-injurious behaviors may initially serve the function of obtaining access to a desired object or activity, however, if the object or activity at that moment is not of the quality or quantity that the individual desires, he may resort to engaging in self-injury to obtain a reaction from another individual. Hence, self-injury serves multiple functions and although initially it was the result of a desire to obtain access to an item or activity, it may have transformed into fulfilling a desire to obtain attention.

Occurrences such as these become even more complicated when an internal drive (sensory function) is responsible for the behavior. It is often difficult to identify the motivating drive of sensory maintained behavior and offer a competing response. Confusion and doubt of initial hypotheses are common responses to behaviors such as these when behavior intervention plans do not produce the desired effect on the target behavior.

When these situations occur, there are multiple options for conducting an ongoing assessment of the individual’s needs and behaviors and examining extraneous variables that may be at play. Furthermore, additional evidenced-based treatments geared towards reducing other interfering symptoms could prove to be beneficial and should be sought out.

When an individual is engaged in what has been determined to be a sensory maintained behavior or a behavior that appears to serve multiple functions and has not been successfully addressed, it is critical to rule out other variables that are likely compounding the problem. Sleep and mood disturbances, side effects of medication, diet, and medical problems can result in physical or mental challenges.

For example, Johnson, Giannotti, and Cortesi (2009) found that 40% to 80% of children with autism spectrum disorders (ASD) experienced insomnia. Furthermore, anxiety, autism symptom severity, gastrointestinal problems, and sensory sensitivities were found to be associated with sleep disturbance in individuals with autism spectrum disorders (Hollway, Aman, & Butter, 2013).

With regard to medication, side effects of commonly prescribed medications for aggression and self-injury, such as Aripiprazole (Otsuka Pharmaceutical Co., Ltd., 2014, December) and Risperidone (Scahill, Koenig, Carroll, Pachler, 2007), can produce unwanted challenges. Two concerning side effects of Risperidone include weight gain and an increase in appetite (Scahill, et al., 2007), and these unintended results carry additional significance with a child who is already displaying aggressive behaviors. Additionally, if the function of the self-injury or aggression was to gain access to food or if food was the most reinforcing item to a child prior to the introduction of the Risperidone, the child’s difficulties could be exacerbated.

A diagnosis separate to an autism diagnosis is another possible explanation for self-injury and aggression, so, it is critical that individuals undergo a thorough evaluation and receive accurate diagnoses. Tsiouris, Mann, Patti, and Sturmey (2003) found that aggression and self-injury was not an equivalent symptom of depression in individuals with intellectual disabilities. As a result, it would not be logical to assume that an individual with an intellectual disability possesses a dual diagnosis of depression due to displays of self-injury or aggression, however, it is worth considering if another underlying disorder is influencing the individual’s behaviors. It is also beneficial to receive a second opinion when there are questions or inconsistencies within a diagnosis.

Medical diagnoses in combination with autism can also exacerbate a child’s impairments. For example, seizure disorders are prevalent in individuals with autism spectrum disorders, particularly when there is a comorbid diagnosis of intellectual disability (Matson & Shoemaker, 2009), and studies have shown that children with seizure disorders display greater impairments in the areas of adaptive behaviors, personal/social abilities, communication, motor abilities, and cognitive abilities than children without seizure disorders (Matson, Neal, Hess, Mahan, & Fodstad, 2010). It is also suspected that seizure disorders impact children with ASD to a greater degree than children with other developmental delays (e.g., spina bifida, cerebral palsy, microcephaly, Down’s syndrome). Undetected medical diagnoses, such as seizure disorders, can offer a possible explanation for delays in progress and conflicting hypotheses of the function of an individual’s self-injury or aggression.

Given these aforementioned circumstances, it is critical that caregivers of individuals with autism consider all possible explanations for self-injury and aggression displayed by their loved ones and that psychological and medical professionals investigate alternate explanations for an individual’s concerning behaviors and inform caregivers of any other possible explanation.

All treatment options explored should be evidenced-based in order to be confident that the treatment will produce the expected outcome and to avoid losing time in which effective treatments could be improving the individual’s life. When challenging behaviors such as self-injury and aggression are of concern, an effective course of action includes conducting an FBA and FA early on to rule out any maintaining sources of reinforcement that could be addressed and possibly avoid unnecessary intrusive interventions with potential side effects, prior to considering other factors that could be impacting the individual’s mood and behavior.

Jenny La Barbera, Psy.D., BCBA-D, is the co-director of NY Behavior Analysis and Psychological Services, an agency that provides assessment and treatment services to individuals with autism and other mental health concerns. She can be reached at or at 646-780-9227.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.


Hanley, G. P., Iwata, B. A., & McCord, B. E. (2003). Functional analysis of problem behavior: A review. Journal of Applied Behavior Analysis, 36, 147-185. doi: 10.1901/jaba.2003.36-147


Hollway, J. A., Aman, M. G., & Butter, E. (2013). Correlates and risk markers for sleep disturbance in participants of the autism treatment network. Journal of Autism & Developmental Disorders, 43, 2830-2843. doi: 10.1007/s10803-013-1830-y


Johnson, K. P., Giannotti, F., & Cortesi, G. (2009). Sleep patterns in autism spectrum disorders. Child and Adolescent Psychiatric Clinics of North America, 18, 917-928.


Matson, J. L., Neal, D., Hess, J. A., Mahan, S., & Fodstad. (2010). The effect of seizure disorder on symptom presentation in atypically developing children and children with autism spectrum disorders based on the BDI-2. Developmental Neurorehabilitation, 13(5), 310-314.


Matson, J. L., Shoemaker, M. (2009). Intellectual disability and its relationship to autism spectrum disorders. Research in Developmental Disabilties, 30, 1107-1115.


Otsuka Pharmaceutical Co., Ltd. (2014, December). Medication guide Abilify. Retrieved from


Scahill, L., Koenig, K., Carroll, D. H., & Pachler, M. (2007). Risperidone approved for the treatment of serious behavioral problems in children with autism. Journal of Child and Adolescent Psychiatric Nursing, 20(3), 188-190.


Tsiouris, J. A., Mann, R., Patti, P. J., & Sturmey, P. (2003). Challenging behaviors should not be considered as depressive equivalents in individuals with intellectual disability. Journal of Intellectual Disability Research, 47(1), 14-21.

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