Self-injurious behavior is one of the most devastating behaviors exhibited by people with developmental disabilities. The most common forms of these behaviors include: head-banging, hand-biting, and excessive self-rubbing and scratching. There are many possible reasons why a person may engage in self-injurious behavior, ranging from biochemical to the social environment. This paper will discuss many of the causes of self-injury and will describe interventions based on the underlying cause.


Functional analysis
Physiological Reasons
Social Causes

Functional analysis

Initially, a functional analysis should be conducted in order to obtain a detailed description of the person’s self-injurious behavior and to determine possible relationships between the behavior and his/her physical and social environment (see Wacker, Northup & Lambert, 1997). The information obtained from a functional analysis should include: Who was present? What happened before, during and after the behavior? When did it happen? Where did it happen? Hopefully, the answers to these questions may help reveal the reason(s) for the behavior.

Prior to data collection, it is important to define the behavior of interest. The focus of the functional analysis should be on a specific behavior (e.g., wrist-biting) rather than a behavior category (e.g., self-injury). Combining several types of self-injury into one general behavior may make it difficult to determine different reasons for each behavior. For example, if a child engages in wrist-biting and excessive self-scratching, there may be different a reason for each behavior (see Edelson, Taubman and Lovaas, 1983). Wrist-biting may be a reaction to frustration, whereas excessive scratching may be a means of self-stimulation.

During data collection, salient characteristics of the self-injurious behavior should be rec