“My [Search Strategies] Keep Missing You”: A Scoping Review to Map Child-to-Parent Violence in Childhood Aggression Literature

Child-to-parent violence is often referred to as one of the most ‘under-researched’ forms of family violence. However, it is closely associated with one of the most widely researched areas of research globally: childhood aggression. How child-instigated aggression can harm parents is widely referred to, but different framings, definitions, and conceptualisations are used which creates problems when attempting to identify the broader literature which may be relevant to child-to-parent violence researchers. Methods: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews, 55 papers were reviewed from EBSCO, PubMed, SCOPUS, and Web of Science to explore how location, field of the researcher, and terminology can impact how researchers conceptualise and frame this form of harm. Results: Three themes were identified (1) child-to-parent violence is a behavioural indicator of childhood distress or developmental needs, (2) children are ‘perpetrators’ of deviant behaviour, and (3) the parents are ‘victims’ of child-to-parent violence. Conclusions: Children and parents are both harmed by child-to-parent violence. It is important that future researchers and practitioners recognise the bi-directionality of the parent-child relationship, and not be complicit in hiding the harms caused by child-to-parent violence by subsuming it under the broader childhood aggression literature.


Introduction
'Child-to-parent violence' (CPV), as a form of child/adolescent-instigated harm, has proved difficult to understand and identify, not only because it does not fit our existing conceptualisations of family dynamics, but also due to the challenges associated with the lack of consensus regarding name, definition, description, or conceptual boundaries. Existing research has framed and conceptualised CPV as a form of domestic abuse [1]; utilised family-based conceptual approaches [2][3][4]; developmental approaches [5][6][7]; and socio-ecological models [8][9][10][11]. However, it maintains 'fuzzy boundaries' as whether it is related to power and control (domestic abuse), a developmental issue (behavioural), a mental health issue or personality type (pathologising), or a parenting problem (problematised) is unclear as current research is contradictory and predominantly exploratory [12].
Measuring the frequency of a phenomenon which has often been considered 'hidden' is difficult [13,14]. Studies have found a higher incidence in community samples, with physical CPV instigated by 4-22% of young people, and verbal/psychological CPV at 33-93% [11,15]; compared with policing samples, whereby CPV accounts for around 1-6% of reported cases of family violence [16]. In all samples which differentiate between the two, there appear to be higher rates of psychological CPV than physical CPV [17,18]. Regarding gender, there is debate as to whether CPV is predominantly instigated by sons or daughters, and this depends on the age of the child, and the definition of CPV used [11]. Definitions and measurements are further problematised in CPV research, as many recognised and validated measurements for CPV have been used outside the age range they were validated on [19]. Furthermore, how families themselves interpret and conceptualise this form of harm, means that CPV is often not framed as a form of family violence at all, but rather a form of childhood aggression, or a behavioural difficulty.

Violence and Aggression
Whilst CPV is often referred to as the most under-researched form of family violence, the broader field of childhood aggression is one of the most highly researched topics globally [20]. This paper is a scoping review of the existing literature on childhood aggression, in an attempt to identify where CPV may be discussed, but named differently, due to different conceptual approaches. The purpose of this paper is to identify where CPV exists in the existing literature, but is explored, understood and conceptualised differently depending on the underpinning societal, structural, and theoretical frameworks. If researchers, practitioners, and families are to benefit from the wealth of existing relevant research, it is important to be clear what relevant research exists which may be utilising different language, concepts, interpretations, or framing.
There are a number of examples regarding how CPV knowledge has changed over time. Several theories of children and childhood are related to child-instigated harms, including the Oedipal complex [21], early child development theories [22], and the most widely used, attachment theory, which is frequently used to demonstrate the importance of consistent responses of a parent to the needs of an infant, but originated from observations of children with 'inappropriate' behaviour [23]. The aim of this paper is to identify the existing literature which explores child-instigated harms within the home directed towards parents, and how it is conceptualised, named, and understood. The hypothesis is: the language used to define CPV will relate to the field of research in which it is used.

Operational Definition
Previous research has highlighted that CPV can be considered 'at-odds' with the broader childhood aggression literature due to a lack of identified harm in the latter [11]. Thus, I have opted to define CPV and its variations as 'any form of physical, emotional, and psychological harm that may be instigated by a child towards their parent'. This includes coercive control, but more detailed inclusion and exclusion criteria will be presented later in this paper. Children refer to the UK legal definition of a 'child' being under the age of 18. Whilst this definition, unlike many other CPV definitions, does not require intent, it does require specific directionality whereby the harm is instigated by the child, and directed at the parent.

Materials and Methods
A scoping review is typically used for mapping the key concepts in a field, and to help with working definitions and conceptual boundaries, all of which are an issue in the field of CPV. It is not about measuring the quality of the literature, but about what is said about the topic of interest. Traditionally, systematic reviews require a team of reviewers to ensure consistency as well as reach, with a higher number of reviewers often reaching more papers and it has been recommended that multiple reviewers be involved in scoping reviews to increase their rigour and consistency [24,25]. However, where time and resources are limited, reviews with a single author can be effective, with the caveat that biases are acknowledged which may impact the number of papers included [25][26][27]. Due to the time and resource limitations of this paper, I have completed this review as a singular author, with an external reviewer selecting 15% of the papers to test the effectiveness of this approach.

Protocol
In this scoping review, I will follow a scoping review framework designed to examine "the extent, range and nature of research activity: this type of rapid review might not describe research findings in any detail but is a useful way of mapping fields of study where it is difficult to visualise the range of material that might be available" [28] (p. 21). This scoping review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) [29]. The initial search was implemented on 22 January 2022. This framework follows five stages, which I will now demonstrate.

Stage One
For this stage, I identified the research question. As scoping reviews do not need a specific question but rather offer an opportunity to explore the boundaries and map the topic of interest I created the question 'how do authors conceptualise the relevant phenomenon in their articles?' 2.1.2. Stage Two I utilised EBSO, PubMed, SCOPUS, and Web of Science core collection using the same search terms for each resource: children OR adolescents OR youth OR child OR teenager, AND violence OR aggression OR hostility OR violent OR anger OR aggressive behav*, AND externali* OR conduct disorder, child* AND Challenging behav*. The exact timeline of the search was 1961-2021 inclusive, as 1961 has been identified as a key point in which research began exploring circumstances of filicide, caused by children and adolescents [30,31].

Stage Three
I outlined and tested inclusion criteria with five CPV-specific papers, and then followed inclusion and exclusion criteria to determine which articles should be included in the review. As the focus of the research was on children, the included papers must include children aged 0-18, rather than focus on harm instigated by adult children. The harm needed to be directional (towards a parental figure), within the home environment rather than in an institution or online, and there needed to be a description of the CPV or use of the term 'explosive'. Therapeutic literature could be included only if there was also a conceptual description of CPV, and teacher ratings of CPV were not relevant.
The literature was excluded if it was not found within a peer-reviewed journal, if it was about uncovering the aetiology or predictors of occurrence, similarly studies on predictors of adult behaviour, prevention or intervention were not included. These included work which focused wholly on the relationship between victimisation and CPV. Parricide was considered a distinct offence [31], so was also not included. Self-harming or suicide studies which did not describe incidents of CPV were removed, as were experimental conditions, animal tests, and studies into substance misuse and its relationship to CPV.
In this third stage, I reviewed titles, abstracts, and when relevant, the full-text papers. I included literature written in English and French, but articles in other languages were excluded as I could not translate them. For articles I could not access through my institution, but up-to-date contact details were available, I contacted the first author of the required paper to request a copy. Of the 20 authors contacted, two sent a copy of their article, with a cut-off date of 15 March 2022. Quantitative, qualitative, and mixed methods studies were included, provided they met the inclusion criteria. An external reviewer checked 15% of the papers to assess whether they would meet the inclusion/exclusion criteria with 55 articles included for the next stage. The review process is available at Figure 1

Stage Five
This final stage was the analysis and writing up stage. Through the tabled literature included in the review, I conducted a frequency analysis, whereby I broke down the various fields, locations, data sources, and terminology used in an attempt to identify where and why certain terminology was preferred over others.
Following the analysis and write-up, a citation check of the identified literature was conducted for June 2021-February 2023 to capture any literature citing the relevant texts found in Table S1 which would have met inclusion criteria based upon the prior four stages, these 13 articles are available in Supplementary File S1 and have been integrated into the discussion section of this paper.
There was a total of 135 different ways in which authors spoke about, or approached CPV (Table 1). From these, 58 of the different ways of referring to CPV gave specific information about who was instigating this form of harm, and recognised that it was directional (to parents, towards parents etc.); 53 of the different ways of referring to this phenomenon focused on the harm experienced by parents (mother abuse, parent battering etc.). However, most of the terminology used in the articles reviewed were very broad in their approach, using teminology such as 'behaviour', 'aggression', or 'violence', which may inform why this particular problem has remained 'hidden', as families request support for 'aggression', which could mean many things, rather than the specific issues experienced when living with CPV.
In Table 1, which papers, fields, and data sources to use for each terminology are identified. The majority of terms were only used in singular papers, rather than being adopted and repeated. The most commonly used term was 'child-to-parent violence', being used across 21 papers [13,14,37,46,47,52,54,56,57,[60][61][62][63]65,67,70,73,75,76,82,84]. CPV was also used by the largest amount of fields and had the widest variety of data. It is likely that the inclusion criteria made this terminology most likely to appear, as terms needed to be directional and descriptive, however, it may also be due to the breadth of fields and data sources. Parent abuse is the second most commonly used term, with 10 references [39,46,47,58,60,61,72,79,81,82]. References to 'abuse' of parents throughout the review were most likely from psychology and specifically criminal psychology; there were also references from the law, criminology, occupational therapy, and social work, although the latter four fields had fewer articles overall than the former [14,36,37,39,40,46,47,52,58,60,61,72,74,78,79,81,82,84]. Twenty-six out of 55 papers directly referred to the phenomenon of interest as a form of violence from a child to a parent, meaning 29 papers did not. Highlighting the possibility of a large gap between the specific CPV literature, and the broader field of childhood aggression. A large proportion of the literature consists of terms relating to 'challenging behaviour', behavioural problems, or similar [33][34][35]40,41,[49][50][51]53,55,64,71,[78][79][80][83][84][85], and there were several studies which focused on children with mental health [48,53,58,66,72,79] developmental [33,45,51,55], or neurodevelopmental needs [49,50,71,80,85]. Similarly, those who focused on preschool children used generalised approaches which included the aforementioned behavioural terminology but also utilised general terminology around 'aggression' [40,41] The data source with the broadest language base was in adoption and fostering, which covered challenging behaviour, distress, and had the highest number of terms related to coercion, and incidents understood to be controlling [34,35,84,85].
The results of this analysis could break the scoped literature into three key themes: (1) CPV as a behavioural indicator of childhood distress or developmental needs, (2) the lens of children/adolescents as 'perpetrators' of deviant behaviour, and CPV as a component of wider aggression or violent profiles, (3) the parents as 'victims' of CPV. In the discussion, I will explore how these three themes relate to the existing CPV literature and the potential challenges of integrating future work.

Discussion
As the scoped literature could be grouped into three separate themes, I present each of these themes in turn.

Indicating Childhood Distress or Developmental Needs
When exploring the challenges associated when parenting a child with developmental, mental health, or neurodevelopmental needs which are not met through traditional parenting strategies, many researchers refer to the parents as 'carers' rather than 'parents' and focus on the strain, burden, and stress experienced, rather than highlight the specificities of the harm [86]. This was also found in this review, as whilst the inclusion criteria required parents to be the ones experiencing 'violence', there were papers which referred to parents as "caregivers", and positioned their child's 'challenging behaviour' or 'behavioural problems' as a "burden", rather than explore the bi-directionality of the parent-child relationship [33,50].
Children with challenging behaviour or harmful behavioural profiles appear to be more common in those with neurodevelopmental disabilities, and there has been some support for CPV to be considered within neurodevelopmental diagnostic assessments [33]. Many families seeking a neurodevelopmental diagnosis for their child described behaviours which would meet the criteria of CPV to be their main concern [33,[87][88][89]. Thus, particularly in social work practice, it has been noted that patterns of behaviour consistent with CPV have been seen and understood, but interpreted as a form of 'challenging behaviour', and so the behavioural and relational patterns of CPV have remained hidden despite its prevalence [84,89].
The developmental component of CPV as an expression of childhood distress was present both within those children with neurodevelopmental conditions, and those younger children, who may not have developed the emotional regulation skills to manage their frustration or distress [40,41,52,68,69]. This was also demonstrated in the updating citation check, whereby some emotional or behavioural expressions which met the descriptive requirements for CPV, were harmful presentations of distress [88,[90][91][92]. As to whether children are attempting to meet their needs in harmful ways has the potential to create an escalation of harmful behaviour over time if those children have needs continue to go unmet [12,34,35,78].
'Emotional and behavioural difficulties and similar terminology were found in the scoping review [35,55,71,78,79,85], however, it is possible that this form of language is conflating issues, as extant literature provides evidence that behavioural indicators are more significant than emotional indicators when looking at how emotional and behavioural difficulties are related to CPV [61,63]. This provides some challenges around understanding risks associated with expressions of mental health difficulties, as whilst externalis-ing behaviours may represent CPV [64,68,69,78,85], mental health difficulties alone will not necessarily mean CPV, despite the number of scoped articles focusing on mental health [48,53,58,66,72,79].

Indicating Deviance
This theme explored how children and young people instigating CPV demonstrated a pattern indicative of a wider aggressive or violent profile, whereby it was conceived that something was inherently 'wrong' or harmful about the way in which the child or young person engaged with the world, rather than approaching CPV as a structural or systemic problem.
Some researchers conceived that CPV could be evidence that the child or young person had a criminal personality profile [63,74,76], or psychopathological traits which promoted such harm [36,66,83]. In the fields of research, it would be expected that psychiatric papers would promote this approach to interpreting CPV. However, the number of psychiatric articles that presented with this framing [34,79], were matched by social work [73,84], despite social work practice being underpinned by anti-oppressive principles. Social work papers, particularly those with a recruitment strategy focusing upon adoption and the perspectives of parents, were the most likely to frame this form of harm as controlling, and coercive [64,84]. The also sat alongside criminologists in the broader research field which often conceptualised CPV as a form of domestic abuse [13,42,44,54,56,57,62,67,70,73,82].
In framing CPV as a form of domestic abuse, it is likely that the specific concerns and risk factors which are distinct from adult-perpetrated intimate partner violence could be ignored, as CPV is subsumed under the wider field of research and practice [60,77]. This is of particular concern when children straddle the identity of both victims of harm, and the cause of the harm [47,93]. It should not be ignored that children are children first, thus when their CPV is harming their relationships, this is bi-directional and escalatory, thus children should also be provided with support alongside their families in navigating this harm [47,93,94].

Prioritising Parents as Victims
Differing to viewing children as 'perpetrators', is the conceptualisation of CPV whereby parents are considered to be 'victims' of CPV. In much previous literature, there was an exploration of how poor mental health in children can impact their aggression and violent behaviour, thus taking a more generalised not directional approach, meaning those harmed by the aggression (parents) were invisible [57]. Similarly, due to the 'less significant levels of harm caused by CPV in comparison to intimate partner violence, the longer term impacts of the ham were ignored [72,79]. However, this approach has changed, with increasing awareness of both the victimisation and stigmatisation of parental experiences [14,37].
As to which fields recognise CPV as a form of victimising parents is contextual, and relates to both the field of research and the participant groups [91,95]. Where it is clear that the topic of investigation was explicitly CPV, any reference to aggression, coercion, or harm was clearly related to CPV, and thus there was more opportunity to explore the experiences of parents. However, when the research explored a broader field, such as challenging behaviour, then who is impacted by the harm was less clear because the directionality of the behaviour is unclear, and one argument as to why there has been an increasing awareness of this form of harm, reflects other forms of family violence whereby there is increasing recognition that family violence is a social problem as much as a private one [46].
Where parental experiences of victimisation were most clear, was in literature whereby mothers had experienced domestic abuse historically, and their child was either being weaponised by an abusive father or was repeating the harm [96]. Related to this, children who had experienced intimate partner violence in their parent's relationship, and then began instigating CPV themselves have been considered to be both compounding how mothers are victimised by violence, whilst also being weaponised and victimised themselves, as children instigating such harm are also experiencing harm [97].

Conclusions
Children who instigate CPV hold the joint identity of victim and perpetrator, and the significance of harm caused to young people through their use of harm should not be conflated with other forms of victimisation, as it is a unique form of harm which requires specific intervention [47,97]. Rather than viewing children as 'perpetrators', and parents as 'victims', there appears to be some benefit in recognizing the bi-directionality of parent-caregiver-child relationships.
Many CPV researchers describe the phenomenon as "under-researched", including myself previously [52], which I now consider to be an incomplete perspective, as demonstrated by this review. There is significant overlap between all of the conceptual framings presented, with significant overlaps as all conceptualisations gave an example whereby child-instigated harms were considered a symptom of a wider development issue, or one component of a wider pattern of harmful behaviours. Similarly, harms instigated by children and experienced by parents are often understood as an expression of distress. Very few articles framed it in a way which fits with existing forms of violence and abuse, thus demonstrating that as the broader field of family violence was recognised as a social problem, not a private one, it brought with it CPV without considering the often 'hidden' nature of child-rearing/parenting [98][99][100].
To conflate the CPV experiences of families under the umbrella of family violence risks losing the nuanced essence of family experiences of child-instigated harms. The differences in approaches and language appear to be related to the positionality and training of the researcher or practitioner and ignores the processes that families engage with when navigating, facilitating, or avoiding the harms instigated by their children. Thus, it is understandable that many researchers and practitioners consider CPV as a problem facing adolescents and their families, whereas younger children are considered 'challenging' or 'problematic' rather than harmful. This is reflected in the extant research as, despite childhood aggression being one of the most commonly researched forms of human behaviour, it is usually related to early childhood development, framed as a 'pathological' or development issue, or framed as 'challenging behaviour'.

Limitations
Whilst this scoping review has provided a significant contribution when attempting to understand how CPV research may be conceptualised and understood across different fields and research groups, it does not provide the systematic body of knowledge that could address how to explore this field in a robust and inclusive way that is provided by systematic reviews. Furthermore, the vast number of studies that were identified in the initial scoping stages does evidence that many studies could be referring to CPV or challenging behaviour, but lack a detailed definition or description of the phenomenon of interest. Thus, many papers may not have been included which provide even broader interpretations of CPV.
As with many scoping reviews, the inclusion criteria are broad enough to capture the boundaries of many fields, but not specific enough to provide specific recommendations for how we move forward. Furthermore, scoping reviews do not require registration and validation through PROSPERO systematic review systems. Indeed, the challenges relating to naming, definitions, and interpretation remain. Furthermore, there are no recommendations for supporting parents with children who would otherwise be considered experiencing a 'caregiver burden' rather than recognising their direct experiences of harm. Nevertheless, the integration of such a wide scope of literature under three themes provides the opportunity to expand our knowledge of this phenomenon, and how it can impact families in their day-to-day interactions.
This review did not include literature which focused on prediction, risk, or aetiology of harm, thus it is unclear whether those factors could have fit within the themes presented here, or been included under new themes. There have been other scoping studies connected to exploring these features, but a meta-analysis is worth considering in the future. There is a significant body of literature which has developed in Spain, which meant many studies could not be included as they could not be translated, this is a significant limitation at this point, due to the wealth of Spanish studies on this topic written in Spanish.

Recommendations
Within practice and research, consideration should be given to the directionality of harmful or distressing behaviours expressed by children and adolescents, whilst also being mindful that language, concepts, and interpretations may not adequately represent the experience of participants or service users. Parents may be using the terminology of 'challenging behaviour', but mean significant harm. As was evidenced in this work, descriptions of the behaviour may assist in the understanding of what families are referring to when they use different concepts, as they may not be translated appropriately across to practitioners when engaging in help-seeking behaviours.