Sleep-Impulsivity-Behaviour (SIB) Study: examining mechanisms underpinning self-harm in children with autism and intellectual disability

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Self-harm, such as biting, scratching, head banging and body punching, occurs at very high rates in children with autism and intellectual disability (ID). As many as 1 in 2 children with autism and ID will self-harm, and in most cases these behaviours persist beyond childhood. Unfortunately, self-harm is a primary cause of family stress, and often leads to placement breakdown resulting in children requiring specialist residential placements away from the family home. Our existing understanding of self-harm in children with autism and ID suggests that interactions in the environment and internal sensory experiences can cause and maintain self-harm. For example, asking a child to complete a school-based task may lead to the child biting themselves; a concerned adult may then briefly remove the task to comfort and protect the child. Over time, a subtle learning process occurs which ingrains these interactions between the child and the environment around them. This learning process makes self-harm more likely, and can also make it more severe. However, whilst this model of self-harm is helpful, it does not identify underlying causes for self-harm beyond these learning processes. Additionally, interventions based on this model can typically only be started after self-harm has already become a learnt behaviour. Our work will uncover causes that drive this learning process, and lead to interventions that target causes to prevent self-harm from becoming established.Based on our previous research, the Sleep-Impulsivity-Behaviour (SIB) Study investigates two potential causes or drivers of self-harm. First, we examine a fundamental brain-based mechanism. Our work suggests that children who self-harm have problems stopping and starting their own behaviour; this brain-based mechanism is called inhibition. However, current assessments of inhibition are often too lengthy or too difficult for children with autism and a co-occurring ID. We have developed new, specialised tests of inhibition that can be used with children with autism and ID, allowing us to test whether problems with inhibition are a fundamental cause of self-harm. These new tests are quick and easy play-based games, and we will compare performance on these games in children with autism and ID who do, and do not show self-harm.Second, we investigate whether poor sleep makes self-harm more likely. We are particularly interested in whether specific sleep difficulties, for example problems with falling asleep, problems with staying asleep, or problems with sleeping at the wrong time in a 24-hour cycle, lead to more frequent and more severe self-harm. We will use wrist worn sleep devices to directly assess children's sleep, providing accurate information about sleep timing and sleep duration. We will use advanced statistical modelling to link children's sleep data with information about their self-harm, collected by parents/carers via a mobile phone App. Our analysis will provide conclusive information about the influence of sleep on self-harm.To complete the SIB Study, we will bring together these two strands of work. In typically-developing children and adults, sleep is known to influence inhibition. Therefore, we think that inhibition may explain part of the relationship between poor sleep and self-harm. In our final study, we will test this idea by running a sleep intervention to improve sleep in children with autism and ID. We will measure inhibition and self-harm to see if improvements in inhibition explain some of the changes in self-harm. Together, all three of these studies will show whether poor inhibition and poor sleep cause self-harm in children with autism and ID. Findings will inform interventions for self-harm, with sleep and inhibition as new, preventative intervention targets. Through our extensive links with clinical services and policy makers, we will ensure that the findings of this project quickly and effectively influence clinical practice.