Chronicity of self-injurious behaviour

In adults with intellectual disabilities, SIB does indeed appear often to be a chronic problem, with persistence rates around 70–80% over periods of up to 20 years, although even in adulthood a substantial minority of those engaging in self-injury later cease to do so. In children at risk for developmental delay, those who begin to self-injure often do so by age 12–24 months, but between very early childhood and the primary school years, approximately half of these children stop self-harming (Baghdadli Reference Baghdadli, Picot and Pry2008). Furthermore, between the early secondary school years and young adulthood, approximately 50% of individuals with autism who self-injure similarly cease to do so (Laverty Reference Laverty, Oliver and Moss2020). Although the part played by services in helping people to control SIB is as yet unclear, these findings suggest that many children can overcome self-injury and that intervention with young people should be prioritised.

Principles of behavioural intervention

Behavioural interventions for self-injury are based on the premise that the behaviour is often maintained by socially mediated reinforcement, i.e. acquisition of instrumental/communicative functions. The success of interventions based on this premise has led to the further assumption that in cases where no socially mediated reinforcement of the behaviour can be discerned, self-injury is maintained by ‘automatic reinforcement’, i.e. sensory or other consequences directly resulting from the behaviour itself.

Functional assessment

Functional assessment is the foundation of behavioural intervention. It should, however, be preceded by the taking of a detailed history, including consideration of health conditions, life events and potentially treatable comorbid conditions such as sleep difficulties, pain and impulsivity/overactivity (Fig. 1). The aim of functional assessment is to identify events that typically precede and follow episodes of self-injury in order to form a hypothesis regarding factors eliciting and maintaining the behaviour. Initial hypotheses can be developed from discussion with parents/carers (or the person concerned) using semi-structured interview schedules, while further information on events preceding and following episodes of SIB may be collected by asking parents/carers (or the person concerned) to complete an Antecedent–Behaviour–Consequence checklist. Hypotheses developed regarding the function(s) of SIB can be further evaluated by use of brief rating scales such as the Questions About Behavioral Function scale.

FIG 1

Care pathway for individuals with self-injurious behaviour (SIB). ABC, Antecedent–Behaviour–Consequence checklist; PBS, positive behaviour support. Adapted with permission from a pathway produced by the Leicestershire Partnership NHS Trust Positive Behaviour Support Pathway Development Group.

Predicting positive response to reinforcement-based behavioural intervention

As both NCR and FCT require identification of the specific reinforcer maintaining the self-injury, they are more difficult to implement in the more than 25% of cases in which automatic reinforcement of the behaviour is hypothesised. Reinforcement in these cases is hypothesised to be a mechanical consequence of self-injury, but it is rarely possible to be certain as to which aspect of the consequences is critical in maintaining the behaviour. The form of the self-injury may offer clues (e.g. eye-poking may be maintained by the visual stimulation it produces). In most cases however, behavioural interventions use reinforcers selected on the basis of a systematic assessment of the person's preferred activities, stimulation and consumables, which are then used in NCR or FCT intervention.

Intervention is less likely to be successful in cases of self-injury maintained by automatic reinforcement than in cases where the behaviour is socially reinforced (Iwata Reference Iwata, Pace and Dorsey1994), and this effect has traditionally been ascribed to difficulty in identifying the reinforcer. The benchmark technique for this identification in applied behaviour analysis is experimental functional analysis, in which levels of self-injury are observed while the person who self-injures is briefly exposed to arranged social environments in which antecedent conditions of interest are reliably present and the person's self-injurious behaviours are reliably followed by a specified consequence. For example the antecedent condition may be a carer being present but preoccupied with another task rather than interacting with the person, and the consequence a brief period of interaction if the person starts to self-injure. Traditionally, automatic reinforcement has been identified as the cause of self-injury if the behaviour occurs at high levels across all conditions of an experimental functional analysis (the person is observed when alone and without any means to occupy themselves) and, for example, when they are provided with stimulation or social interaction.

Recently, however, Hagopian et al (Reference Hagopian, Rooker and Yenokyan2018) have shown that cases in which levels of self-injury are higher in an ‘alone’ condition than in a more stimulating environment usually respond well to reinforcement-based interventions, whereas those in which levels are high across all conditions in an experimental analysis rarely do so. This identification of a predictive behavioural marker for response to reinforcement-based intervention represents a first step towards effective stratification for treatment in cases of automatically reinforced self-injury.

Further steps towards stratification for treatment

Hagopian et al's (Reference Hagopian, Rooker and Yenokyan2018) research raises the issue of whether it is possible to identify other potential markers of responsiveness to treatment for self-injury. Even where experimental analyses identify external sources of reinforcement as maintaining the self-injury, function-based behavioural treatments are not efficacious in 6–11% of cases (Iwata Reference Iwata, Pace and Dorsey1994). Several clinical attempts to further delineate treatment-relevant subtypes of self-injurious behaviour (Table 1) have yielded some consensus on a distinction between individual cases where self-injury is primarily maintained by reinforcement, or has evolved into a habitual or impulsive response to interpersonal or environmental challenges, or has become ‘compulsive’ (such that the person is driven to attempting to physically restrain themselves from self-injuring). The presence of self-restraint may therefore be a further predictive behavioural marker for resistance to reinforcement-based intervention (Hagopian Reference Hagopian, Rooker and Yenokyan2018). No comparable marker has yet been identified for cases where self-injury may have evolved into a habitual/impulsive response to specific situations, although we (Furniss Reference Furniss and Biswas2020) have recently suggested that failure to respond positively to a brief trial of NCR may be a clinically useful indicator.

TABLE 1

Convergence of proposals for stratification of cases of self-injurious behaviour (SIB)

Reprinted and adapted by permission of Springer Nature from Furniss & Biswas (Reference Furniss and Biswas2020). © 2020 Springer Nature.

Differentiating treatments

Although predictors of resistance to reinforcement-based interventions may help to avoid committing the energies of families and other carers to interventions when prospects of success are limited, the benefits of identifying predictive behavioural markers would increase enormously if they could also identify cases where alternative treatments might be effective. Case studies have described progressive exposure to the eliciting situation using a hierarchy of steps (organised as task steps or along dimensions such as degree or duration of exposure to the situation) as helpful for self-injury evoked by particular environmental situations, and such interventions may be specifically helpful for cases of habitual/impulsive self-injury.

Further research is needed to determine whether the potential behavioural indicators described above are indeed able to distinguish individuals who will benefit from reinforcement-based versus exposure-based interventions. In the meantime, clinicians should seek skilled behavioural intervention for young people who self-injure and consider behavioural predictors of outcome in treatment planning, including stopping over-medication in people with intellectual disability, autism or both (Royal College of Psychiatrists 2021).