Self injurious behaviour is a very common problem in people on the autism spectrum. For example, according to Minshawi et al (2014),
“To begin with, while SIB is quite common in individuals with ASD, it is not endemic only to this population; however, those with ASD appear to be at an increased risk for engaging in SIB over and beyond that of other populations. Researchers looking at lifetime prevalence in those with ASD suggest that approximately 50% engage in some form of SIB, even if just at one specific period of their life span. Point prevalence estimates indicate that SIB affects upwards of 25% of persons with ASD when surveyed at a distinct time point.
Self injurious behaviours are even more common in people on the autism spectrum with additional issues, such as learning disabilities. For example, according to Oliver and Richards (2015)
“A number of recent studies report an association between ASD with associated intellectual disability and self-injury with prevalence estimates ranging 33%–71%. There is growing evidence that the prevalence of self-injury within ASD is higher than might be expected when degree of intellectual disability is controlled for. A meta-analysis of prevalence studies has shown that those with ASD are approximately six times more likely than those who do not have the diagnosis to show self-injury. The association between degree of intellectual disability and prevalence seen in intellectual disability is evident in ASD (although the samples of those with intellectual disability are likely to include people with ASD). “
Sometimes self injurious behaviour is transitory and short in duration, lasting only days or weeks, while at other times it can persist for months or years. For example, according to Minshawi et al (2014)
“… SIB in those with ASD and other developmental disabilities is considered to be a pervasive and chronic problem. The general long-term course of SIB suggests that the behavior first manifests in childhood and progresses into adolescence with a corresponding increase in prevalence and persistence well into adulthood. Taylor et al found that in a cohort study of 49 adults diagnosed with ID, many with comorbid ASD and SIB, 84% continued to exhibit SIB 20 years later (ie, as part of a longitudinal follow-up study on SIB persistence), with no significant changes in topography (ie, type of SIB) or severity."