Can self-injurious behaviour be reduced by medication in individuals with intellectual disabilities?


Self injurious behaviour (SIB) is commonly seen in individuals with intellectual disabilities (ID) and has been defined as any activity that self inflicts injury or harm to oneself (NAS, 2015). This may include behaviours such as head banging, biting, hair pulling and scratching.

The severity of these actions can range from mild scratching and biting, to broken bones or life threatening injuries. Self injury can be highly distressing for the individual, as well as the family and carers who witness it.

Many theories have been put forward  as to why people with ID may engage in SIB. Some researchers theorise that these behaviours are a coping mechanism in response to too little or too much sensory stimulation, whilst others suggest a communicative motive.

One line of theory is that individuals with ID who display SIB have a disturbance in their opioid brain system creating a higher threshold for pain. Secondly, SIB may also induce an opiate ‘euphoric’ feeling which may reinforce the individual to continue.

One theory is that SIB may induce an opiate ‘euphoric’ feeling reinforcing the individual to continue

One theory is that SIB may induce an opiate ‘euphoric’ feeling reinforcing the individual to continue


Roy et al. (2015) aimed to review the effectiveness of medication known as opioid antagonists, which block the feelings of euphoria that individuals may experience while engaged in SIB. They were interested to see if this medication would reduce SIB in individuals with ID.

They performed a systematic review of current literature to analyse findings from studies that had aimed to answer this research question.

The inclusion criteria for studies in this review included:

  • Randomised control studies only
  • No date restriction on publication
  • Both studies including children and adults who had a diagnosis of ID (IQ lower than 70) were included
  • Individuals taking concurrent medications were allowed to take part
  • Individuals with dementia were excluded


After reviewing the studies yielded from the initial search criteria, 10 studies were included in the final review. In total these studies included 124 participants, the majority of which had a diagnosis of a severe to profound intellectual disability. All the participants in the studies were inpatients in a residential setting.

  • 49 out of the 124 participants had a co-morbid diagnosis of autism
  • All studies used a varying dosage of opioid antagonist medication, ranging from 0.5mg/kg-100mg/kg. This medication was namely called Naltrexone.
  • The majority of studies used the occurrences of SIB post medication as the outcome measure

Key finding:

In the studies reviewed, only half of the findings showed a significant reduction of SIB in individuals with intellectual disabilities who were taking opioid antagonist medication.


The findings from Roy et al’s (2015) systematic review appear to show no reliable link between the administration of opioid antagonist medication and the reduction of SIB in those with intellectual disability.

A number of the studies they reviewed did show a significant impact, for example Symons et al. (2001) who found a reduction in SIB by 33% in 3 out of 4 participants, and Sandman et al. (1993) found 18 participants showed a reduction in SIB with one dosage of Naltrexone (P < 0.0001), with more that half showing a 50% reduction ( P < 0.0001), and a third having a 75% reduction ( P < 0.02).

However, Willemsen-Swinkels et al. (1995) found that both 50 mg and 150 mg Naltrexone had no effect on self injury but increased stereotypy, placebo treatment was preferred by carers and there was no correlation between the effects of single dose of Naltrexone and long-term administration.

Zingarelli et al. (1992) had one subject with partial decrease in behaviours but overall, Naltrexone did not reduce SIB.

Strengths and limitations

In terms of the reliability and validity of these findings, it is important to take into account that all the studies used small participant samples and therefore, the significant findings may not be generalised to the ID population.

However, the presence of some significant findings may prompt more research into this area using a larger sample size.

The studies reviewed also had a wide range of publication dates, with no real current findings being reported. Some of the findings were as much as 20 years old. A more up to date study would be advantageous.

Secondly, as Roy et al. acknowledge themselves, participants were all inpatients in residential settings. This meant that the findings took account of the large number of individuals with ID who now live supported in the community or in their own homes with family, possibly reflecting the age of the studies sampled.

A final note:

The systemic review here has suggested that while in some circumstances opioid antagonist medication did reduce SIB, the authors could not conclude why this may be; warranting more investigation into the causal factors involved for individuals with ID.

Carr (1977) suggested that because SIB has multiple motives, the intervention should be individualised to the person with ID and match the specific function of the SIB (e.g. attention, escape, sensory stimulation, etc.).

It may be that opioid antagonist medication is useful alongside other interventions, and that a person centred care plan, including multidisciplinary input could provide a more holistic approach to understanding individual cases of SIB in those with an intellectual disability.

However, the findings here may warrant more current investigation into the effect of  opioid antagonist medication with a larger sample size that can be generalised more reliably to the learning disability community.

Opioid antagonist medication may be useful alongside other interventions, in the context of a good person centred plan

Opioid antagonist medication may be useful alongside other interventions, in the context of a good person centred plan

Roy, A., Roy, M., Deb, S., Unwin, G., & Roy, A (2015), Are opioid antagonists effective in reducing self-injury in adults with intellectual disability? A systematic review. Journal of Intellectual Disability Research, Vol 59 (1), pp.56-67.

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Rachel Allan

Rachel Allan

Rachel Allan was previously a Practice Lead working for The Royal Mencap Society, supporting and developing good practice in services for individuals with a wide range of complex disabilities. She graduated in psychology and went on to study both developmental psychology and mental health at post-graduate levels. Rachel has previously worked in many different care and educational settings for children, young people and adults with a wide range complex learning disabilities. She has also worked within academic research, specifically completing a two-year research associate post looking at the mental health of individuals with profound and multiple needs (PMLD). She is particularly interested in person centred planning, supporting the mental health and well-being of people with complex disabilities, and more recently, the effects of trauma and abuse in this group of individuals. Having recently taken voluntary redundancy from her role at Mencap, Rachel is now enjoying some free time (!?) to explore her personal interests while she assesses what may be the next chapter in life.....

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