Effects of a topical anesthetic on non-socially maintained self-injurious behavior.

In the present study we hypothesized that the self-injurious behavior (SIB) of a 12-year-old male diagnosed as having autism and severe mental retardation was maintained by automatic reinforcement. Further, we hypothesized SIB served a sensory reinforcement function related to sensation at the skin surface. The participant engaged in high rates of SIB in the form of self-slapping. A functional analysis resulted in undifferentiated findings. Additional observations indicated that SIB occurred only to exposed skin surfaces. To test for a sensory function, we applied a topical anesthetic to the participant's skin. SIB was reduced by 20 to 60% after application of the dermal anesthetic. These results support an automatic reinforcement hypothesis. Implications for treatment are discussed.