Pain perception in looked after young people with self-harm

Lead Research Organisation: King's College London
Department Name: Child and Adolescent Psychiatry

Abstract

The overarching aim of this proposal is to investigate the causes and underpinning mechanisms of self-harm. Specific objectives are (1) to investigate pain sensitivity in young people at a very high risk of self-harm; (2) to investigate pain sensitivity in young people with the first episode of self-harm; (3) to investigate pain sensitivity in young people with multiple episodes of self-harm.
Suicide is the second leading cause of death in adolescents and self-harm is the best predictor of death by suicide. 30-40% of Looked after young people (LAYP) have self-harmed, approximately 3-4 times more than other young people. The risk of suicide in LAYP is 3-4 times greater than in adopted young people.
The way we deal with pain may be important in why people self-harm by self-cutting. People that are less sensitive to and without an aversion towards the anticipated pain of self-harm by self-injury may be less likely to experience a barrier towards self-harm and are more likely to actually engage in self-harm. Young people who self-harm by self-cutting are more likely to die of suicide than young people who self-poison. Self-harm may be associated with differences in the endogenous opioid system, a key system involved in pain: e.g., individuals engaging in self-harm have lower resting levels of beta-endorphin and enkephalins, which are parts of the opioid system. Studies published to date indicate that people with self-harm are less sensitive to pain. However, many questions remain unanswered: (1) Are pain sensitivity differences to do with self-harm itself or to do with psychiatric disorders that often accompany self-harm? (2) Are pain sensitivity differences present before self-harm starts? (3) Is pain sensitivity linked with the frequency of self-harm?
In order to investigate these questions, 104 young people will participate in this study. LAYP aged 12-17 (the age at which self-harm typically starts and its prevalence peaks) will be recruited via Glasgow register of LAYP (approximate n=900). 26 LAYP with no self-harm, 26 with a single episode of self-harm, 26 with multiple self-harm episodes (5 or more episodes) and 26 healthy controls (HC) will be included. The LAYP and HC groups will be age and sex matched. Measures of self-harm, dissociation (altered state of consciousness which often accompanies self-harm), pain catastrophising, clinical diagnosis and measures of social functioning will be obtained.
The primary outcome measure in this proposal is cold pain threshold. Assessment of thermal pain thresholds will be done. We will use a device called contact thermode to measure it. In addition, all young people will be tested with a standard set of sensory tests. We will also investigate pain sensitivity when LAYP think they are socially excluded using a virtual ball-toss game called Cyberball. The reason to use Cyberball is that most self-harm occurs following a perceived social exclusion and it is important to understand if pain sensitivity is particularly low at times of social exclusion.
After the initial assessment, pain thresholds will be measured at rest and post-stress. On the basis of previous work in adults with self-harm, we anticipate that we would detect cold pain threshold of ~15C in HC and ~ 8C in LAYP with multiple self-harm, with two other groups demonstrating intermediate values.
Pain sensitivity may provide one of the key insights into the nature of self-harm and might form the basis of future proposals investigating pain sensitivity and self-harm in longitudinal cohorts as well as future prevention and treatment studies.

Technical Summary

Suicide is the second leading cause of death in adolescents and self-harm is the best predictor of death by suicide. Looked after young people (LAYP) have a lifetime prevalence of self-harm of 30-40%, 3-4 times greater than that in the general population.
The aim of this proposal is to investigate the aetiology and mechanisms of self-harm. Objectives are to investigate pain sensitivity in youths with (1) a very high risk of self-harm; (2) the first episode of self-harm; (3) multiple episodes of self-harm.
Previous studies indicate that people with self-harm have a higher pain threshold. What is not knows is: (1) how specific is the relationship between clinical variables and pain sensitivity? (2) Are pain sensitivity differences present before self-harm starts? (3) Is pain sensitivity associated with frequency of self-harm?
To investigate these questions, 104 LAYP aged 12-17 will be recruited via Glasgow register of LAYP (n=900). 26 LAYP with no self-harm, 26 with a single episode of self-harm, 26 with multiple episodes (5 or more) and age and sex-matched 26 healthy controls (HC) will be included.
The primary outcome measure will be cold pain threshold. Ramped thermal stimuli will be applied using a Peltier-based contact thermode followed by standardised sensory tests. Social exclusion will be simulated using Cyberball. Pain thresholds will be measured at rest and post-stress. Between-group comparisons will be done using two-sample t-tests and 2 way mixed ANOVA including one within-subject factor (baseline versus stress induction) and one between-subject factor (frequency of self-harm).
We anticipate cold pain threshold differences of ~6.5C (SD 8.1, d=0.86) between HC and LAYP with multiple self-harm, with two other groups demonstrating intermediate values. With the alpha set at 0.05 (two-tailed) and power at 80%, 26 patients in each treatment group will be required.
Understanding pain sensitivity may provide a key insight into the nature of self-harm.

Planned Impact

Almost all human disease is associated with some form of pain. This grant addresses a vital question of the relationship between early adversity, pain perception and self-harm and will further our understanding of possible mechanisms of self-harm development with the hope that the insights provided will directly translate into new treatments for self-harm. Self-harm in young people is a prevalent and rising problem in the UK with few evidence-based interventions which generally have limited impact. At the same time, the cost associated with self-harm is likely to be substantial. Byford and colleagues (2009) estimated the long-term costs, over 6 years, of a cohort of young people who participated in a Randomised Controlled Trial following an episode of self-harm. Lifetime and current (6-month) costs were calculated and compared with general population controls to explore costs incurred by the UK general public sector. Resource-use data included inpatient and day-patient services for psychiatric reasons, pregnancy or child birth, foster or residential care, supported accommodation, special education, prison and criminal justice, and social security benefits. Over the longer term follow-up, the self-harm group used substantially more public sector resources in terms of special education, foster care, residential care or other supported accommodation, and social security benefits. They also spent more time in prison or police custody and had a number of hospital attendances for psychiatric reasons, in comparison with the general population control group. Lifetime differences in the costs of key services were large and statistically significant. The self-harm group incurred significantly more costs per year in terms of psychiatric hospital contacts, supported accommodation, special education and social security benefits. In total, the self-harm group cost over £1,500 per year compared with only £65 per year in the control group (mean difference £1,440). The overall hital costs associated with self-harm (£36 mln a year in Emergency Department assessments alone) and the number of young people who present with self-harm is rising. The indirect costs of self-harm in terms of lost productivity, days lost from work, as well as costs to families and carers, are unknown but are likely to be substantial given its prevalence within the UK. Elucidating the aetiology and the underpinning mechanisms of self-harm in young people may help in the efficient use of available healthcare resources and may maximise the health benefits for people who self-harm and can potentially reduce costs to the UK healthcare system and society in the long term.
Academic users will benefit from the study's experience and technology development. Other users may want to use our methods for children and adolescents in other developmental, neuropsychiatric, neurological or medical fields, in particular, autism spectrum disorders and other conditions with potentially altered pain perception. We will make the methods available to other users via collaborations. The benchmark treatment for self-harm is psychological therapy, however, both efficacy and availability of this treatment is poor. Consequently, alternative treatment development for self-harm is a major priority and a major challenge for both state-funded and private sector. This project may lay foundations of a different approach to the treatment of self-harm in the future.
Researchers involved in this project will develop analytic, statistical, communication and writing skills, will improve their ability to work as part of a team and dealing with Looked after young people and their carers.
Locally, we anticipate that the study will increase identification rates of looked after young people with self-harm, reduce the number of young people who self-harm without access to treatment and promote awareness of self-harm in the community.

Publications

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