From maternal childhood maltreatment to children’s emotional-behavioural problems: what can be done to break the link
I have written this piece together with Xuemei Ma, a PhD student at King's College London who, like me, is particularly interested in the relationship between early life adversity and child mental health. We recently investigated this topic in a systematic review.
Childhood adversity: effects on physical and mental health during lifetime
Childhood maltreatment, defined as exposure to sexual, physical, emotional abuse or neglect (i.e., unwanted sexual experiences, physical punishment, experiences of rejection, criticism and lack of care for the child’s needs) before 18 years of age, is a serious public health issue. Every year, millions of children suffer from abuse and neglect, with a worldwide prevalence ranging between 12.7% and 26.7%. This prevalence is an underestimation, as many cases are not reported, particularly those of emotional abuse and neglect, which often don’t come to clinical attention but can equally have devastating consequences on the child’s well-being.
Childhood maltreatment increases the risk of developing psychiatric disorders, such as depression, anxiety, bipolar disorder, substance abuse, psychosis and personality disorders. It has also been associated with an earlier age at onset of these mental health problems, and with a more severe clinical presentation (e.g., more frequent episodes and severe symptoms, increased risk for suicide attempts, more hospitalizations and multiple disorders in the same individual, less response to treatment). Childhood maltreatment is also associated with an increased risk of developing medical disorders such as coronary artery disease, cerebrovascular disease, type 2 diabetes, asthma and cancer, and with a generally significant reduction in life expectancy.
Biological mechanisms are involved in this increased vulnerability. These include: increased inflammation in the body (i.e., increased activation of the immune system, the system that fights against infections); alterations in the functioning of the hypothalamic-pituitary-adrenal (HPA) axis, the system that gets activated in case of stress, and consequently higher levels of cortisol, the hormone released during stressful situations; genetic and epigenetic processes (i.e., modifications in the expression of DNA following environmental experiences); and changes in brain function and structure.
Childhood adversity: effects through generations
Childhood maltreatment can also have negative effects across generations. Women who experienced maltreatment in childhood are more likely to have children who also experience adversity (often not by their mothers but by other adults inside or outside the family or by peers) as well as emotional and behavioural problems.
The mechanisms through which maternal traumatic experiences can pass across generations are multiple, and these may start during pregnancy or even before, through changes in the uterine environment and in the expression of DNA.
Many psychological factors are also involved; for example, women who experienced childhood maltreatment can have more difficulties in bonding and interacting with their children.
Despite this evidence, it is also true that the majority of mothers who have experienced childhood maltreatment go on to have healthy children who do not experience stress, maltreatment, or mental health problems.
It is therefore important to understand how maternal adversity and child outcomes are linked, to identify which factors could be targeted in preventive interventions.
Potential important factors involved in the transmission of childhood maltreatment
As mentioned above, we recently investigated, in a systematic review, which factors are important in the relationship between maternal experience of childhood maltreatment and less optimal emotional and behavioural development in their children.
Maternal depression, occurring in the child’s first three years of life, plays a key role in whether a mother’s childhood maltreatment can impact her children’s emotional-behavioural development. Women who experienced childhood maltreatment are indeed at an increased risk of antenatal and postnatal depression, and this depression, in turn, increases the risk of offspring being exposed themselves to childhood adversity as well as developing emotional and behavioural problems during childhood and adolescence. This provides a vehicle for the intergenerational transmission of childhood maltreatment, suggesting that the perinatal period is an optimum time to provide interventions to improve women’s mental health and protect their children as well.
Maternal insecure attachment is another important linking factor. An insecure attachment develops when a child feels that the caregiver is not reliably available or responsive. The style of attachment developed in childhood has a lasting impact on how individuals build relationships in adulthood, including with their children. Mothers with a history of childhood maltreatment are at increased risk of developing avoidant attachment (one type of insecure attachment), which is then linked to an increased risk for the children to develop insecure attachment themselves, leading to more emotional and behavioural problems. Conversely, a more secure maternal attachment can lower the risk of emotional and behavioural problems in children. Therefore, working with women to improve the relationship with their infants should be a key focus of intervention, to minimise the potential negative effects of maternal childhood maltreatment on their children.
Parenting styles also play an important role. Maternal childhood adversity is associated with an increased risk of less optimal parenting practices, such as the use of hostile parenting and harsh discipline, which further increase the risk of aggressive behaviours in their children. On the contrary, positive parenting styles such as highly sensitive parenting (parenting behaviours that are child-centered, engaged, warm, and stimulating) could promote children’s mental well-being. It is therefore important to increase awareness of the importance of positive parenting for child behaviour and mental health. Notedly, the effect of parenting practices on children's behaviour may be more pronounced in girls compared with boys.
Other factors need to be further investigated. For example, emerging research has shown that maternal nutrition can impact offspring’s mental health. Maternal poor nutrition during pregnancy (such as inadequate intake of energy, protein, essential fatty acids, and various key micronutrients) can have negative effects on the offspring’s mental health. A lower adherence to a healthy diet during pregnancy has been related to higher levels of inattentive and aggressive behaviours in the offspring during childhood. This suggests that nutrition-based interventions in pregnant women could mitigate the potential negative consequences in children.
Additionally, children’s healthy diet during early life may also reduce the likelihood of developing a mental illness. In early childhood, an increased intake of unhealthy foods (such as chips, sweetened desserts and beverages), and a lower intake of nutrient-rich foods (such as vegetables, fruit, egg, and fish products), increase the risk of developing mental health problems. Therefore, targeting a child’s diet might be another way to break the transmission of maternal childhood maltreatment on child’s mental health.
Fathers play a key role in the family environment, from the very beginning. For example, low partner support is a strong risk factor for both antenatal and postnatal depression, which can further increase the risk of mental health problems in children of mothers with a history of childhood maltreatment. Additionally, fathers also have a significant influence on children’s development. For example, father’s language input promotes child’s expressive language at age 3; and a father’s emotionally responsive parenting style can lower the risk of depressive symptoms in pre-adolescence. Additionally, a positive father-child relationship reduces the risk of engaging in delinquent behaviours and substance use in adolescence, with a stronger effect seen in boys. Thus, improving fathers’ mental health and their relationship with their children could also have a protective effect on child’s mental health
In conclusion, working on these factors (maternal perinatal mental health and style of attachment, parenting practises, diet and father’s involvement) with targeted interventions could help minimise the potential negative impact of maternal childhood maltreatment on children's mental well-being, helping them pursue a more positive life trajectory.