I have often heard that about 20 to 30% of individuals with an autism spectrum disorder (ASD) will exhibit significant symptoms of irritability and/or aggression including quickly changing moods, severe tantrums, and self-injurious behaviors (SIB). These behaviors are more prevalent in low functioning individuals and/or those that are non-verbal. Medications like antipsychotics (also known as neuroleptics), although largely ineffective in treating anomalies of social interaction and communication, are often used to treat these symptoms. Side effects (e.g., weight gain, sedation, new onset diabetes, elevation of serum triglyceride levels) of these medications may be significant and limit their acceptance by parents, especially when given over long periods of time.
Self-injurious behavior, in particular, is the most significant problem faced by a number of ASD individuals. These behaviors include head banging, hair pulling, scratching, hand biting and even eye gouging. Biting of the lips, tongue, and fingers is more characteristic of a syndromic form of autism, i.e., the Lesch-Nyhan syndrome.
Self-injurious behaviors are upsetting and frustrating to parents and health care professionals. Indeed, once they are evident it is difficult to leave affected individuals alone for fear of significant injury. The constant vigilance and consequent tension is only superseded by the feeling of guilt if the child injures himself/herself.
Laura Schreibman in her excellent book “The Science and Fiction of Autism” describes the case of a boy who exhibited SIB. Knowing that this was the case for their son, the parents removed anything from his room they thought could harm him. Despite due diligence the parents unfortunately forgot to remove the metal frame of their son’s mattress. One fateful night the child’s repeated head banging prompted severe brain injuries and ultimately his tragic demise.
Head banging is a common type of SIB in ASD and does not require an object from the surroundings for it to happen. Some patients hit themselves by banging their fists against their eyes or ears. Cauliflower ears are a common outcome of this behavior. I was told of one particular patient where chronic head banging lead to a deformation of the frontal bone causing a protrusion or, in medical terms, frontal bossing.
Figure: Cauliflower ear in a boxer. Trauma may cause a blood clot under the skin of the ear. The clot disrupts the connection of the skin to the ear cartilage and in so doing severs its blood supply. The cartilage, deprived of its blood supply, shrivels up to form the classic cauliflower ear.
Figure: Frontal bossing (pronounced forehead) in a child.
Head banging may be seen occasionally in normally developing infants where it usually occurs at night and disappears by about 3 years of age. In a normally developing infant some people consider this behavior to be part of a sleep disorder or, in the case of a pre-verbal child, a way of venting frustrations and making their displeasure known to their parents. In ASD head banging occurs at either night or day, may extend to an older age, and is accompanied by other signs of developmental delays and/or motor stereotypies, e.g. body rocking.
Although head banging against a wall or wood floor would be expected because of the commonality of these objects it is not unusual for ASD individuals to select the sharp edges of metal objects. This selection does not appear to be with the intent of fracturing a bone but rather that of creating intense pain. In this regard what may have been intended as a bout of head banging against a sharp metal object may end up causing severe eye damage or other unintended consequence.
It is often said that SIBs are usually prompted by demands of the physical and social environment. Some researchers consider it a form of self-stimulation, a way of releasing tensions and calming the individual. These behaviors have also been related to the presence of seizures and in one particular type of SIB, eye gouging or poking, to low levels of calcium. Mary Colemean who described the relation of low calcium levels to eye poking has stated that calcium supplements may cause a substantial diminution of the SIB as well as improvements in communication. Another possible metabolic cause is low levels of serotonin or high levels of dopamine. It is not unusual that people taking drugs that increase dopamine levels, amphetamines and apomorphine, initiate self-injurious behaviors.
Many years ago I had the opportunity to work in a project at the NIMH collecting tissue from dogs that constantly licked and chewed on their paws to the point of bleeding. You could say that this condition could be taken as an animal model of either SIB or of obsessive compulsive behaviors in humans. Many veterinarian believed the paw licking behavior was related to boredom on the part of the dogs, anxiety, allergies or an obsessive compulsive trait. Genetics definitely play an important role in pathological paw licking. Purebred or a cross breed constitute approximately 95% of the paw licking dogs. Mutts with genes of more than two breeds constitute less than 5% of the paw licking dogs. In our study, laboratory testing revealed that the dogs had low serotonin levels and treatment with an antidepressant (in order to elevate the serotonin levels) reduced the symptoms.
Some people believe that intense pain is associated with an endorphine rush which may provide a euphoria-like feeling to the individual. Conditions associated to abnormalities in pain sensitivity usually exhibit SIBs. Clinical trials in autism and also in congenital analgesia using an opiate blocker (e,g., naltrexone, naloxone) aiming to reduce the euphoria feeling have diminished the frequency of self-injurious behaviors.
In many cases a precipitating cause may not be obvious. In a future blog I will detail another possible explanation to SIBs in autistic individuals and how the same may lead to possible means for intervention.
Addendum 9/9/2013: The following note was written to me by my friend Ira Cohen, Chair of Psychology at NYS IRBDD:
I liked your note on SIB – don’t forget to mention undiagnosed mood disorders as playing a role.
My colleague John Tsiouris, had a case of a young girl from a very large family who had severe autism and self-scratching to the point of bleeding. Upon questioning, she was found to have an older sister with bipolar. Looking at her other behaviors which included curling herself into a ball and unexplained crying, she was placed on an SSRI and almost immediately improved.
Just some food for thought