Project title: Suicide, Autism and Autistic Traits

Type of research:

Pilot Study

Background & Scientific Rationale:

Suicide is a devastating consequence of mental illness. There has been little research focused specifically on people with autism who commit suicide. Retrospective research by our group found that the prevalence of lifetime experience of suicidal ideation (SI) in people diagnosed at a specialist adult clinic for autism was extremely high (66.2%), as were plans or attempts (P/A) to commit suicide (34.7%) (Cassidy et al. 2014). Adults with autism were significantly more likely to report lifetime experience of SI than individuals from a general UK population sample, or a sample with medical or psychotic illness. Interestingly, patients reporting suicide plans or attempts had higher Autism Spectrum Quotient (AQ) scores (a quantitative measure of autistic traits) than those not reporting suicidal behaviour, suggesting that autistic psychopathology may contribute to suicidal behaviour. No published data exist on the prevalence of autism in suicide victims. Prospective studies are needed to determine rates and risk factors for suicidal ideation, plans, and attempts in adults with autism in a variety of settings. These figures are critical to inform suicide prevention priorities and to assess the impact of prevention strategies.

Research aims:

  1. To determine the prevalence of autism in individuals who have committed suicide
  2. To confirm the prevalence of lifetime and current experience of suicidal ideation, plans or attempts in adults with autism, and associated risk factors
  3. To determine the extent to which autistic psychopathology may be a risk factor for suicidal behaviour
First study: The aim of the first study was to establish whether autism (diagnosed and/or undiagnosed) is over-represented among people who died by suicide in the UK.

Methodology: Coroners’ inquest records for the period 2014-2016 where the conclusion was suicide or open were requested from two UK counties.

These records were scrutinised for evidence of autism, and were categorised into 4 groups: (1) Definite Diagnosis (where the inquest file included information stating that the individual had a diagnosis of autism), (2) Strong Evidence (where there was at least one reference to the person possibly having autism and two independent judges agreed that the individual met all the criteria for autism but had no diagnosis), (3) Possible Diagnosis (where two independent judges agreed there were many indications of autism, but there were gaps in the evidence), and (4) No Evidence (where the individual showed no signs of autism or there was not enough information to know whether or not the person had autism).

219 Coroners’ inquest records were assessed, 153 of which were ruled a likely suicide according to ICD-10 criteria. 11.8% of records had some evidence of autism, which is significantly higher than the prevalence of autism in the UK general population (1%). Of these, 0.7% were classed as Definite Diagnosis, 1.3% as Strong Evidence, and 9.8% as Possible Diagnosis.

Findings: This study highlights that a significant minority of cases of death by suicide in the UK show evidence of the person potentially having had undiagnosed autism. The study also provides further evidence of increased suicide risk in autistic people. It suggests the need for clinicians to screen for suicidal thoughts and behaviours when assessing patients for possible autism, as well as considering screening for autism in people who have suicidal thoughts and/or behaviours.
These results relate to one of the two counties from which records were requested.

Second study: The aim of the second study was to measure autistic traits in adults who reported having made at least one suicide attempt.

Autism is diagnosed as a categorical condition (i.e. a person is thought to either have or not have autism); however, variation in individual difference traits that are associated with autism are distributed throughout the general population.

Methodology: Autistic traits were measured using the Autism Spectrum Quotient (AQ), which is a self-report measure. Scores on the AQ were compared between people who had made a suicide attempt and people in the general population.

Findings: Over 40% of people who had attempted suicide had an AQ score above the cut-point indicating possible clinical significance (≥26). AQ scores were significantly higher in adults who had attempted suicide compared to adults from the general population, and even higher in adults who had attempted suicide more than once compared to adults who had made one suicide attempt.

A better understanding is needed of the risk and protective factors for suicide in people who have elevated autistic traits, regardless of whether they have a clinical diagnosis of autism.

Potential Impact

  • Together, these studies will be valuable for training for medical and allied professionals in an effort to improve suicide prevention, and highlight autistic people as a particularly vulnerable group in the population
  • A recent debate on mental health and suicide in autism was held in the House of Commons UK, which drew on the team’s research as evidence. Preliminary results from the analysis of Coroners’ inquest records were presented and discussed at the Interagency Autism Coordinating Committee in the US. Colleagues based at Universities of Coventry, Newcastle, and Nottingham, with funding from Autistica, ESRC, and CLAHRC, led three Stakeholder events in San Francisco (US), Newcastle (UK), and Coventry (UK). This accompanied a call to action published in The Lancet Psychiatry.
  • In addition, colleagues leading the ESRC funded Mental Health in Autism project created a video series and guidelines in partnership with autistic adults who have experienced mental health problems and suicidal thoughts and behaviours. The videos explore some of the challenges faced, and the aim is to provide a greater voice to autistic people who may be experiencing distress, in order to raise awareness among GPs and other primary care staff.
  • On international Autism Awareness Day in 2017, Professor Simon Baron- Cohen, Director of the Autism Research Centre at Cambridge University and President of the International Society for Autism Research, highlighted the urgent need for suicide prevention in autism in his keynote speech to the United Nations.

For further information on this project, contact Professor Simon Baron-Cohen, Professor of Developmental Psychopathology,


Cassidy S, Bradley L, Shaw R and Baron-Cohen S. Risk markers for suicidality in autistic adults. Molecular Autism. 2018; 9:42. DOI: 10.1186/s13229-018-0226-4 (PDF)

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