Introduction
People with severe mental illness (SMI) are at increased risk for all forms of violent victimisation [
1]. Domestic and sexual violence victimisation is common among people with SMI, and victims show higher levels of psychosocial morbidity following violence than in the general population [
2]. Although, there is an established association between childhood maltreatment and adulthood violent victimisation in the general population [
3,
4], there is little evidence for the SMI population. People with SMI are a particularly vulnerable population, suffering from a range of mental and physical morbidity, social disadvantage, and elevated risk of premature mortality [
5,
6]. It is therefore, particularly important to advance our understanding of early risk factors for later difficulties in this population as this might help pave the way for preventative interventions.
Childhood maltreatment refers to both childhood abuse (emotional, physical and sexual) and childhood neglect (emotional and physical). In the general population there is strong evidence for the association between childhood abuse and adult abuse and trauma, even after adjustment for confounding variables [
3]. A prospective cohort of abused and neglected children with matched controls found that the increase in risk of adult victimisation associated with childhood abuse and neglect was specifically an increase in risk of interpersonal violence such as physical and sexual assault/abuse [
4]. All types of childhood abuse and neglect increased the risk of interpersonal violence in adulthood with no evidence for specific associations between subtypes of childhood maltreatment and specific forms of victimisation in adulthood [
4]. Although, the same pattern of increased risk was observed for men and women with experiences of childhood maltreatment, the effect on increased risk for the event “coerced into unwanted sex” was significantly stronger for men than for women [
4]. In both the general population and among people with SMI, women are at greater risk for domestic and sexual violence [
7‐
9] and thus, risk factors and potential mediators for intimate violence must be explored by gender.
As the cause of domestic and sexual violence is always ultimately the behaviour of the perpetrator, it can be difficult to clarify the mechanisms by which a person’s negative childhood experiences could increase their vulnerability to later violence. Grauerholz uses an ecological framework, proposing that personal, interpersonal and sociocultural factors associated with childhood abuse may increase the risk of exposure to potential perpetrators, or increase the likelihood that potential perpetrators will act aggressively [
10]. Factors associated with childhood abuse in the general population such as lack of resources, social isolation, drug and alcohol abuse, psychiatric symptoms and stigmatization [
11‐
13] may all increase the risk of a perpetrator acting aggressively, due to the perception of the victim as an easy target and feeling more justified in behaving aggressively, as well as decreasing the ability of the victim to respond assertively [
10]. Many of the factors considered to be the potential mediators of the relationship between childhood abuse and adult victimisation are very prevalent in populations with SMI, regardless of abuse history.
The prevalence of childhood maltreatment among people with SMI is extremely high [
14,
15]. Experiences of childhood maltreatment are associated with more severe psychiatric symptoms and more complex clinical manifestations among people with SMI [
16,
17]. People with SMI also have a much higher prevalence of both past-year and lifetime experiences of domestic and sexual violence compared to general population samples [
8,
18‐
20]. Sexual and domestic violence among people with SMI is associated with substance abuse, homelessness, psychiatric illness severity and history of childhood abuse [
8,
21].
Despite the high prevalence of victimisation across the lifetime, and the association of victimisation with psychopathology, there have been very few studies which have looked at the association between childhood maltreatment and domestic and sexual violence in adulthood among populations with SMI. The studies that have been conducted to date have often excluded men with SMI, and have not adequately adjusted for confounding factors. In addition, previous studies have not investigated associations between adult victimisation status and the occurrence of different forms of childhood maltreatment and abuse [
21‐
24].
Aims of the study
We aimed to explore the association between childhood maltreatment and adulthood sexual and domestic violence victimisation among people with SMI, investigating gender differences, potential mediating factors, and the risk associated with different forms of childhood maltreatment. Our primary hypothesis was that the experiences of moderate to severe childhood maltreatment would increase the odds of adulthood domestic and sexual violence victimisation among both men and women with SMI.
Discussion
Principal findings
We found a very high prevalence of childhood maltreatment and adulthood domestic and sexual violence victimisation among both men and women with SMI. For both men and women, experiences of moderate to severe childhood maltreatment were associated with two to six times the odds of domestic and sexual violence victimisation in adulthood. All forms of childhood abuse independently increased the odds of victimisation in adulthood. The strength of association between childhood maltreatment and adulthood domestic violence victimisation were similar for men and women. However, the association between childhood abuse and adulthood sexual violence victimisation appeared to be stronger in men than in women.
Strengths and limitations
We used detailed, validated measures of childhood abuse and adulthood victimisation, and studied associations in both men and women. Most studies investigating domestic and sexual violence have exclusively focused on women and to date, the full picture of associations in both men and women has been unknown. We have shown that childhood abuse increases the odds of adult victimisation in both men and women with SMI. We were also able to investigate the effect of different forms of childhood maltreatment on adulthood violent victimisation, including emotional abuse and neglect, the effects of which have seldom been investigated.
Nevertheless, our study had limitations. The low response rate (52 %), may have introduced selection bias into the sample. Low response rates are a common challenge in studies of SMI participants, with ‘gatekeeping’ being a particular problem when participants are contacted through care co-ordinators, as was the case in this study. It is possible that people who have experienced victimisation would not want to take part in a study requiring disclosure of these experiences and this can lead to underestimation of the prevalence of victimisation. The prevalence of victimisation obtained in this study is in keeping with that reported in previous studies, which suggests that our sample was not particularly unusual.
Missing data on the variables of interest in this study is another limitation. With sensitive questions about abuse and victimisation, it is possible that data are not missing at random, as it is possible that people with a history of abuse may feel less comfortable answering questions about abuse than those without that experience. However, as there may be similar effects on answering questions referring to abusive experiences in childhood and adulthood, the effect of missingness may not bias the associations between childhood and adulthood abuse too greatly, and again the result would be to underestimate the strength of associations.
A further limitation is that all experiences of victimisation were self-reported and thus potentially subject to information bias. There is a possibility that those reporting adult victimisation may be more likely to recall and report childhood victimisation, as victimisation in adulthood may revive childhood memories, which would lead to an overestimation of the association. Generally, it has been found that people with SMI are reliable in their reports of childhood and adult abuse, although men with SMI may be less reliable regarding reports of sexual abuse [
29]. It is thus possible that the lower prevalence of violence victimisation in men is due to under-reporting. A recent study using archival data of the minimization-denial subscale of the CTQ found that minimization of childhood maltreatment is common among community samples and psychiatric patients, and that this may underestimate associations between childhood maltreatment and associated outcomes [
30].
As the study was a cross-sectional survey, it is not strictly possible to infer causality between the outcome and the exposure. Although reverse causality is unlikely, due to the time-bound nature of exposure (in childhood) and outcome (in adulthood), there may be many other explanations for the association observed, including recall bias and unmeasured confounding.
Comparison with previous literature
The high prevalence of childhood abuse found in this study is similar to that previously reported in people with SMI [
14,
15]. The prevalence of childhood neglect was very high in both women and men with SMI. This should be investigated in more detail in SMI populations, as neglect has been shown to have adverse mental health outcomes in the general population [
31], and yet most studies with SMI populations have focused on abuse. The finding of an increased risk of domestic and sexual violence with experiences of childhood maltreatment is in line with previous research among populations with SMI [
21,
22,
24]. Women with SMI with a history of childhood abuse were over three times more likely to experience adult sexual assault in one study [
24]. Another study looking at men and women with SMI found that patients who had been sexually abused as adults were more likely to have sexually abused as children, but physical abuse in childhood was not associated with physical abuse in adulthood [
22]. Other research has demonstrated the high prevalence of sexual and physical abuse among men and women with SMI, and the association with history of childhood abuse [
21]. Our findings extend past literature by showing the association between childhood maltreatment and adulthood victimisation among men and women with SMI, and by exploring the effect of different forms of childhood maltreatment, such as emotional abuse and neglect, that previous studies have not investigated.
Many of the associations between childhood maltreatment and adulthood sexual violence victimisation were weaker among women than men. This is likely due to the difference in prevalence of sexual violence victimisation experiences in adulthood between men and women. As the majority of women in our sample (62 %) had experienced sexual violence, compared to 22 % of men, it is likely that specific childhood risk factors do not show such a strong association with what is sadly and shockingly such a prevalent outcome for women with SMI. Using an ecological framework to understand sexual and domestic violence victimisation [
10], it follows that for women with SMI, there are so many risk factors for violence present, that the experience of childhood maltreatment may have less independent effect on vulnerability to later victimisation. Particularly for sexual violence, as it is less prevalent in men, it is likely that individual risk factors such as childhood maltreatment will have a greater effect on the risk of revictimisation.
The results of this study also suggest that emotional abuse in childhood increases the odds of adulthood domestic and sexual violence victimisation in both women and men. This is an important finding, as previous studies have neglected the effect of forms of childhood maltreatment other than physical and sexual abuse on adulthood victimisation. This finding adds to the evidence suggesting that rather than there being something about specific (i.e. physical and sexual) abusive experiences in childhood that makes people more vulnerable to similar abusive experiences in adulthood, broader stressful childhood experiences may affect the life-trajectory negatively in terms of complex social and behavioural outcomes which may increase vulnerability to violence. Indeed, one large prospective study in the general population found that childhood maltreatment had little direct impact on lifetime mental health outcomes when stressful life events were controlled for [
31].
Implications
As abusive experiences in both childhood and adulthood are associated with poorer mental health outcomes in people with SMI, the findings of this study highlight the importance of clinicians rigorously assessing patients’ trauma history, and addressing the complex needs of patients who have been victimised. The risk of re-traumatisation in institutional settings as well as private must be considered. Interventions to address victimisation in adulthood do not take early experiences into account. Future research is therefore needed to understand the mechanism linking childhood maltreatment and adulthood victimisation. It may be the case that experiences of victimisation in early life influence risk of later victimisation in this causal manner, via changes in social and psychological development and the severity of illness. On the other hand, the association may simply reflect continuity of adversity across the life course, with early victimisation a marker of social disadvantage that is still present in adulthood and increasing risk of victimisation. Interventions aimed at helping people with SMI deal with the consequences of traumatic experiences may lead to improved clinical outcomes. NICE guidelines state that trauma-focused psychological treatment should be offered to PTSD sufferers regardless of the time that has elapsed since the trauma [
32]. People with SMI who have been victims of childhood maltreatment should potentially be considered candidates for such treatment. The results of this study also highlight the importance of addressing a wider range of traumatic experiences in childhood, such as emotional abuse, which have previously been neglected.