Risk factors for self-harm in people with epilepsy

Hayley C Gorton,Darren M Ashcroft,Matthew J Carr,Roger T Webb,W Owen Pickrell

doi:10.1007/s00415-018-9094-2

Abstract

ObjectiveTo estimate the risk of self-harm in people with epilepsy and identify factors which influence this risk.MethodsWe identified people with incident epilepsy in the Clinical Practice Research Datalink, linked to hospitalization and mortality data, in England (01/01/1998–03/31/2014). In Phase 1, we estimated risk of self-harm among people with epilepsy, versus those without, in a matched cohort study using a stratified Cox proportional hazards model. In Phase 2, we delineated a nested case–control study from the incident epilepsy cohort. People who had self-harmed (cases) were matched with up to 20 controls. From conditional logistic regression models, we estimated relative risk of self-harm associated with mental and physical illness comorbidity, contact with healthcare services and antiepileptic drug (AED) use.ResultsPhase 1 included 11,690 people with epilepsy and 215,569 individuals without. We observed an adjusted hazard ratio of 5.31 (95% CI 4.08–6.89) for self-harm in the first year following epilepsy diagnosis and 3.31 (95% CI 2.85–3.84) in subsequent years. In Phase 2, there were 273 cases and 3790 controls. Elevated self-harm risk was associated with mental illness (OR 4.08, 95% CI 3.06–5.42), multiple general practitioner consultations, treatment with two AEDs versus monotherapy (OR 1.84, 95% CI 1.33–2.55) and AED treatment augmentation (OR 2.12, 95% CI 1.38–3.26).ConclusionPeople with epilepsy have elevated self-harm risk, especially in the first year following diagnosis. Clinicians should adequately monitor these individuals and be especially vigilant to self-harm risk in people with epilepsy and comorbid mental illness, frequent healthcare service contact, those taking multiple AEDs and during treatment augmentation.

Highlights

People with epilepsy are twice as likely to die by suicide compared to those without epilepsy [1]
Compared to the matched cohort, the epilepsy cohort was more deprived and more likely to have been diagnosed with any mental illness, treated with psychotropic medication or opioids (Table 1)
The overall incidence rates for first self-harm event (Table 2) were greater in the epilepsy cohort (5.0 per 1000 person-years, 95% CI 4.4–5.6) than in the comparison cohort (1.3 per 1000 personyears, 95% CI 1.3–1.4)

Summary

Introduction

People with epilepsy are twice as likely to die by suicide compared to those without epilepsy [1]. Nonfatal self-harm, defined as any type of intentional self-injury or self-poisoning [2], may lie on the causal pathway between epilepsy and suicide. Risk of hospitalization for self-harm in people with epilepsy has been estimated in two studies [4, 5]. Singhal et al reported a relative risk of 3.9 (95% CI 3.8–4.1) for selfharm in the year following hospitalization for epilepsy and 2.6 (95% CI 2.5–2.7) in subsequent years [4]. Meyer et al estimated the hospital self-harm presentation rate in people with epilepsy to be 2.04 (95% CI 1.85–2.25) times that of the comparison group [5]. Meyer et al identified epilepsy diagnosis from the self-harm reporting form, as part of a multi-centre study, and confirmed with review of medical

Methods

Results

Conclusion