The ‘alarmingly weak’ evidence base for the ‘toxic trio’

Despite its centrality in child protection policy and practice, the research base relating to the combined impact of parental mental ill-health, substance misuse and domestic abuse is lacking, academics argue

Research results post-it note on mouse
Photo: Artur/Adobe Stock

By Guy Skinner, Paul Bywaters, Andy Bilson, Robbie Duschinsky, Keith Clement and Dustin Hutchinson

The term ‘toxic trio’ was coined to describe the risk of child abuse and neglect stemming from a child’s exposure to i) domestic violence, ii) parental mental health issues and/or learning disability, and iii) parental alcohol and/or drug misuse.

The concept emerged from research commissioned by the Department for Education, including the analyses of serious case reviews. Capturing policy makers’ and professionals’ imaginations, the ‘toxic trio’ became a shorthand for identifying how risk factors combined in child protection practice and embedded in assessment processes, national data collection and the family justice system. But how good is the evidence that the toxic trio combine to significantly add to risk to children?

Overlapping with adverse childhood experiences research (Lacey, R and Minnis, H, 2019), there is evidence that each of the ‘trio’ of factors in isolation can lead to worse child outcomes, although this is far from comprehensive. But, as the Children’s Commissioner for England had found (2018), there is “very little recent and representative empirical evidence on the prevalence of these factors” or their consequences for child abuse or neglect.

We therefore set out to systematically review the range and strength of the research base underpinning the ‘toxic trio’ in English child safeguarding policy and practice.

Through an exhaustive literature search of 6,316 papers, only 20 papers met our criteria for inclusion: recent quantitative evidence examining a combination of at least two of the ‘toxic trio’ factors and linked to child outcomes.

We also consulted parents from the Families Research Advisory Group at the National Children’s Bureau about the underlying concept and our findings.

‘Alarmingly weak’ evidence base

The central findings from our review was that the evidence base for the ‘toxic trio’ is alarmingly weak and lacking in the precision, detail and depth on which policies should be based. There is no research giving definitive answers on how prevalent these factors are in combination, nor how many children are or are not experiencing abuse or neglect as a result. There are no large-scale, high-standard, nationally representative studies.

A second key finding was that hypotheses about how these and other factors may interact to cause child abuse and neglect have barely been formulated, never mind tested. Our review found exceptionally little consideration, either theoretical or empirical, of the causal mechanisms that link combinations of these particular factors with maltreatment.

Third, the studies that do exist rarely define the factors in sufficient detail or describe well how they were measured. For example, for mental illness, there were major outstanding questions left unaddressed: do all diagnostic categories have the same consequences? Are maternal and paternal illness equally significant? Does the length and timing of the illness matter? What exactly is it about the illness that affects the child? Or is it other factors associated with mental illness, such as stigma or the loss of employment, income, friendships or self-esteem, that have an impact?

Fourth, the absence of an intersectional approach in most of the research means that we know even less about how these factors differentially affect children and young people. It remains unknown how the trio factors affect children of different ages or identities, with different backgrounds or living in different contexts.

Fifth, almost no attention has been paid in the studies to the role that might be played by the quality and availability of remedial or supportive services for parents or children. For instance, given that over half of all children will have had experience of maternal mental illness by the age of 16 (Abel, KM et al, 2019), an outstanding question is whether well-treated mental illness is as damaging as untreated mental illness in conjunction with other ‘toxic trio’ factors.

Sixth, no studies have examined in any detail whether or how the availability of social, economic and environmental resources might influence the impact of the factors on childhood maltreatment, in addition to the impact of services. There is a steep social gradient in child protection interventions (Bywaters, P et al, 2018). But does this result from differential prevalence of the factors in families of different socio-economic status, or from differential access to formal or informal help?

In conclusion, despite the term’s currency, we found little quality evidence of the incidence of the ‘trio’ factors in child maltreatment, little consideration of intersectionality and minimal attempts to build models explaining the supposed relationships. Parental mental ill- health, domestic violence, drug or alcohol use,and parental learning disability are undoubtedly important factors in children’s lives. However, they are not the only significant factors and the social and economic context in which these issues are experienced have a major impact on their consequences for children.

‘Self-fulfilling bias’

This review shows that the evidence base for the ‘toxic trio’ does not sufficiently justify its current central position in shaping child protection policy and practice.

The parents we consulted viewed the ‘toxic trio’ concept as offensive and alienating as well as liable to lead to self-fulfilling bias in social work assessments.

The focus on the ‘trio’ has crowded out other factors, which would lead to a different orientation to practice, one that recognises that securing and maintaining trust between parents and services is a key issue, underpinned by an understanding that good parenting requires resources as well as skills.

Research is urgently needed to examine the comparative importance of the ‘toxic trio’ against other relevant factors. At the household level, these include demographic factors such as parental age, parental separation or marital/ co-habiting status; socio-economic factors, such as the impact of poverty, poor quality housing or homelessness, precarious employment or unemployment; and identity factors, such as ethnicity.

Covid-19 has underlined evidence of the impact of social inequalities on parenting capacities and family relationships. Directors of children’s services report that it is becoming increasingly challenging to fulfil their statutory duties to provide help for children in need and children and families face less support, more investigations and more removals of children in response to their difficulties.

With our evidence in mind, the next steps for the sector must be to unlearn the assumptions lying behind the ‘toxic trio’, to rethink the purpose and direction of child protection and to build a well-constructed evidence base to inform policy, service provision and practice.

This research is part of Living Assessments, a five-year research project on children’s health and social care funded by the Wellcome Trust in a partnership between the National Children’s Bureau, University of Cambridge and University of Kent. 

The full journal article was published in the Children and Youth Services Review. 

Guy Skinner is visiting researcher at the University of Cambridge’s institute of criminology, Paul Bywaters professor of social work at the University of Huddersfield, Andy Bilson emeritus professor of social work at the University of Central Lancashire, Robert Duschinsky head of the applied social science group in the University of Cambridge’s primary care unit, and Keith Clements senior researcher and Dustin Hutchinson senior research and policy analyst at the National Children’s Bureau

8 Responses to The ‘alarmingly weak’ evidence base for the ‘toxic trio’

  1. Marion January 28, 2021 at 12:37 pm #

    Thanks to the authors for this. I am a retired CP social worker whose daughter has a long history of mental illness including compulsory admissions to hospital. Her partner has been worn out by the unthinking, cliche reliant judgements of social workers when he has asked for help. I sat in on one of the respite assessments and was appalled at the aggressive tone and casual dismissal of his needs and circumstances. When I outed myself as an ex-social worker I was accused of an “ambush” and “impeding” the assessment. We were told in a very cold horrible and adversarial way about the toxic trio and rather more menacingly that children are likely to be removed from families for their protection and wellbeing because of it. All my lovely son in law was asking was for a few hours of respite care once a month so he could take his older child to a soft play centre. I am ashamed at what social work seems to have become. Relince on theories and practice routines appears so uncritical and non-reflective. We too were busy, we also had difficulties and limited resources. But we worked as a team to help each other to practice well. Why have social workers become so jaded that rather than tackle the inequalities, the poverty, the grinding injustices in our communities, they seem to seek fault in family relationships instead?

    • Alison January 30, 2021 at 11:06 pm #

      You are 100% percent right it is easier to blame the family than look for solutions to help because services have been cut so much. I hope you and your family get the help you need.

  2. inksmith January 29, 2021 at 9:43 am #

    Surely “mental ill health” is just more stigmatising of people who have mental health problems? Or are we really suggesting that someone who’s mental ill health is under control is more of a risk to children than someone who has uncontrolled physical health problems? Because that just sounds like prejudice to me.

    Actually, I’m pretty sure that applies to substance misuse as well, since I’d guess that includes people who have their substance misuse problems under control or are in treatment.

  3. Claire S January 29, 2021 at 5:51 pm #

    I can’t believe the term “toxic trio” is still being used. Mental illness is just that, an illness, not a toxin. If you start with this thinking, whether verbalised or not, you’ll alienate the very people you need work with before you’ve begun.

  4. Opinionated January 30, 2021 at 7:51 pm #

    It’s a disappointing article. There is a plethora of available research highlighting the impact of mental health, substance abuse and family violence and the correlation between these. The impact on the adults involved and the resultant impact on parenting capacity and childhood experience.
    Just because referring to things as ACE’s is the current trend, does not detract from where the majority of ACE’s stem from.
    Toxic trio is a guide. Assessment is a tool to consider the level of impact and protection.

  5. Harry January 31, 2021 at 11:19 pm #

    If we had proper support services and trusted social workers to do their jobs having listened and heard peoples stories, we would not be stigmitising service users and demeaning them with labels that never acknowledge the strengths they invariably have. Mental illness, addiction and familial abuse can and do have negative impact but there is no correlation in the way as suggested by Opinionated. No amount of sobriety, good mental health and positive domestic relationships can bypass adverse life opportunities and endemic poverty. If we were honest we would acknowledge that in our profession we have collagues who are substance abusers and whose personal relationships are harmful to their psychological wellbeing. Yet they function as good social workers because of the options they have to compensate. I had a team manager who was a registered heroin addict, the best, the most supportive, the most empathetic, the most honest manager and supervisor I ever had.

  6. Terry McClatchey February 2, 2021 at 11:48 am #

    It is easy to restate the problem that having children exposed to any or all of domestic abuse, parental mental illness or substance abuse is not good for them. The “toxic trio” label is a provocative way of stating the obvious that known risk factors compound each other. The hard bit is to develop clear evidence on the positive and generalisable actions that can be taken to mitigate these risk factors. Declaring something to be bad doesn’t make it go away.

  7. Jane February 24, 2021 at 7:57 am #

    I have been working with children in care for 15 years and I would say nearly every single child I’ve worked with during this time was in the care system due to any one , or all three , of the toxic trio reasons – that’s not to say that all parents who fall under any of those 3 categories should have their children removed – but they are definite factors for some people being unable to care safely for their children.