Main findings

Over two-thirds of perpetrators in our sample (64.5%) had accessed mental healthcare in the period reviewed in the DHR reports. Over half (51.1%) had received a psychiatric diagnosis before the homicide, most commonly depression and anxiety disorders. The high prevalence of depression among IPH perpetrators is consistent with recent systematic reviews of mental disorders and perpetration of intimate partner violence^{Reference Saunders, Landau, Howard, Fisher, Arseneault and McLeod17} and general violence.²¹ In our sample, perpetrators of family homicide had higher rates of diagnoses of psychotic disorders; a recent systematic review has shown high rates of past-year patient-reported and relative-reported violence by people with severe mental illness towards relatives, particularly those acting as caregivers, ranging from 19 to 77%.^{Reference Wildman, MacManus, Harvey, Kuipers and Onwumere22}

Perpetrators’ mental health diagnosis or service use do not imply causality between mental disorders and the homicide. A recent study of general population surveys demonstrated an association between a diagnosis of depression and intimate perpetration partner violence, yet the direction of the association was unestablished.^{Reference Saunders, Landau, Howard, Fisher, Arseneault and McLeod17} Although serious violence is rare in individuals with a mental health diagnosis, it remains an important adverse outcome for clinical services to consider, as the absolute rates of violent crime over 5–10 years are between 6–10% in individuals with schizophrenia-spectrum disorders.^{Reference Whiting, Lichtenstein and Fazel14} Comorbid substance misuse or personality disorder increase the risk of IPH in males with a psychiatric diagnosis.^{Reference Yu, Nevado-Holgado, Molero, D'Onofrio, Larsson and Howard15}

Substance misuse and a history of violence were common overall, particularly among perpetrators who had used mental health services. Alcohol and drug misuse have been associated with intimate partner violence victimisation and perpetration,^{Reference Afifi, Henriksen, Asmundson and Sareen23,Reference Cafferky, Mendez, Anderson and Stith24} and three in four men receiving treatment for substance misuse have reported a lifetime history of perpetrating intimate partner violence in a cross-sectional study.^{Reference Gilchrist, Radcliffe, Noto and d'Oliveira25}

Most perpetrators had a history of DVA perpetration (69.9% of the total sample, and 76.7% in the IPH-MH group); it was less common in the FH-MH group, although still present in more than half of individuals (53.3%). The figure for DVA history includes cases in which it was only revealed to the reporting panel after the homicide had been committed, and in a number of cases such history was not known to healthcare services.

Self-harm or suicide attempts among perpetrators of domestic homicide were common (43.54% in the whole sample, and 60% among perpetrators who had used mental health services), and 21% of the reports involved attempted or completed suicides by the perpetrator after the homicide; the frequency of those incidents was similar across both mental health service-using and non-service-using groups. Studies have reported an increased risk of suicide attempts among perpetrators of family violence in military populations and among male perpetrators of IPH within the criminal justice system.^{Reference Ursano, Kessler, Naifeh, Herberman Mash, Nock and Aliaga26,Reference Conner, Cerulli and Caine27} Police data have shown that offenders charged with domestic homicide were three times more likely to have a history of suicidality than individuals arrested for other offences.^{Reference Button, Angel and Sherman28} However, the direction of causality remain unclear.

There were important differences in the pattern of mental health service use among the IPH and the family homicide groups. Perpetrators of family homicide had much higher rates of psychiatric diagnoses, whereas perpetrators of IPH had higher rates of no diagnosis. Although it is not possible to reach conclusions about the level of risk posed by the different diagnostic categories based on this sample, our findings suggest that perpetrators of family homicide who use mental health services tend to have more enduring mental health problems compared with perpetrators of IPH, and the higher prevalence of use of community mental health teams (66.7% v. 30% in the IPH group) and forensic and custody mental health services (16.7% v. 5.5% in the IPH group) reflects that characteristic. A higher number of family homicide perpetrators had last used mental health services over 1 year before the homicide (42.8% v. 27.2% in the IPH group), although the difference was not statistically significant. Notably, over one in three perpetrators of IPH used mental health services in the month before the homicide.

IPH perpetrators’ higher prevalence of emergency services’ use (31.1% v. 16.7% in the family homicide group) and of lack of formal diagnoses or follow-up indicate that their service use tends to be episodic and crisis-driven. This poses challenges when assessing risk, owing to the lack of access to background information and continuity of care. IPH perpetrators were more likely to have a history of DVA perpetration and to have (or be a partner or ex-partner of someone who had) children under the age of 16, which makes it vital that assessments by mental health services include information about partner (and ex-partner) and family, even if mental health follow-up is not required.

Strengths

To our knowledge, this is the first study to analyse the patterns of mental health service use of perpetrators of domestic homicide using data from DHR reports in England and Wales. By conducting separate analyses of IPH and family homicide, our study added to the current evidence base on these two different types of domestic homicide and the differences between these groups.

Limitations

We searched for reports systematically in order to minimise the risk of bias in the sampling of reports, but it was not possible to obtain all reports published to date.

DHR reports are written retrospectively with the knowledge that a homicide has been committed. Public inquiries on violence perpetrated by people with mental illnesses have been criticised for hindsight bias.^{Reference Szmukler29} Additionally, DHR reports are not written for research purposes, and data on ethnicity, age, mental health and substance misuse are often missing.

Our results report on patterns of mental health service use by the subgroup of DVA perpetrators who committed homicide, therefore our findings may not be generalisable to perpetrators of non-fatal forms of DVA.

Implications for clinical practice and policy

Our findings add to the evidence formulated by NICE guidelines³⁰ and statutory guidance for the Domestic Abuse Act 2021,³¹ which strongly support the need for health services to take an assertive role in prevention by identifying patients who are at risk of being victims of DVA. NICE guidelines recommend targeted enquiry about DVA experiences or victimisation for individuals accessing mental health services for anxiety or mood disorders, self-harm, suicidality and substance misuse, but there were no explicit recommendations on enquiry in DVA perpetration.^{Reference Chantler, Robbins, Baker and Stanley10}

The evidence from wider research of an association between mental disorders, particularly depression^{Reference Trevillion, Williamson, Thandi, Borschmann, Oram and Howard16} and substance misuse,^{Reference Wildman, MacManus, Harvey, Kuipers and Onwumere22–Reference Cafferky, Mendez, Anderson and Stith24} and perpetration of intimate partner violence, alongside data from DHR reports and police arrests demonstrating a higher incidence of suicidality among perpetrators of domestic homicide, indicate that perpetrators of DVA may access mental health services during times of crisis. Additionally, there is evidence from qualitative studies that male DVA perpetrators may present to healthcare services seeking help for the consequences of relationship difficulties and may disclose DVA perpetration at times of crisis and when they feel listened to by clinicians.^{Reference van Rooij, ten Haaf and Verhoeff32–Reference Hashimoto, Radcliffe and Gilchrist34} These factors suggest that healthcare services can have an important role in identification of DVA perpetration.

The Linking Abuse and Recovery through Advocacy for Victims and Perpetrators (LARA-VP) resource by King's College London advocates for the assessment of risk of violence and abuse (including emotional abuse and coercive control) towards family members, partners and ex-partners as part of the general violence risk assessment for people presenting to mental health services.^{Reference Yapp, Oram, Lempp, Agnew-Davies, Feder and Trevillion35} Currently there is little official guidance and few standards for health services in the UK on case finding or other forms of identification of DVA perpetrators, including methods of enquiry and the appropriate response to a disclosure of DVA perpetration. There is an urgent need for further research and development of interventions for perpetrators who use mental health services, which should take into account the variety of diagnoses demonstrated in our sample.