An investigation of self-injurious behaviors in adults with severe intellectual disabilities.

Self-injurious behavior (SIB) is commonly observed among individuals with intellectual disability (ID) living in state-run supports and services centers. Specific examples of SIB include poking oneself in the eye; harming oneself by hitting, scratching, or pinching; and pica (i.e., swallowing objects causing bodily harm). Previous research has focused on SIB in individuals with ID more generally without focusing on specific levels of ID or taking into account other important personal variables. This study examined 45 adults with severe ID living in two large state-run facilities in the Southeastern United States who were separated into groups for comparison (ASD and non ASD; verbal and nonverbal). Data was collected on the presence of SIB using the Autism Spectrum Disorder-Problem Behavior Adult Version (ASD-PBA). A two-way analysis of variance (ANOVA) was conducted to determine if there were significant differences between groups on rates of SIB. Individuals with ID and ASD exhibited significantly higher rates of SIB than individuals with only ID, F (1,43)=50.84, p<0.05. Furthermore, verbal individuals had significantly higher rates of SIB than nonverbal individuals, F (1,43)=57.612, p<0.05. There was a significant interaction between the effects of ASD diagnosis and verbal ability on rates of SIB, F (1,43)=50.84, p<0.05. The implications of these findings in the context of other research on ID, ASD, SIB, and verbal abilities are discussed.