Self injurious behaviour is any form of aggression that is directed by an individual against themselves which results in physical damage. That damage may include bruising, lacerations, bleeding, bone fractures and breakages, and other tissue damage.
Self injurious behaviour is very common in autistic people, especially if they also have learning disabilities. Sometimes the 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.
There are risk factors associated with some autistic people which make it more likely that they will self injure. These include internal factors, such as specific genetic syndromes or painful medical conditions; interpersonal factors, such as self injury becoming a learnt behaviour; and external factors, such as a lack of control over their living environment. In practice an autistic individual may self injure for a range of different but inter-related reasons.
Self injurious behaviours can cause all sorts of problems for autistic people beyond the immediate damage to a specific part of the body. It can cause damage to other parts of the body, such as the brain, and even lead to death. Self injurious behaviour can also result in people being further restricted in what they can do and being further excluded from society.
Please see our detailed entry on Self Injurious Behaviour and Autism