Parental mental illness and early years of life
Results from a cohort of offspring of parents with schizophrenia or bipolar disorder
Theme: Perinatal mental health
A linear association has been demonstrated between the number of early risk factors a child is facing in fetal life and the first years of life and the level of functioning at age seven. Children of parents with schizophrenia or bipolar disorder are already in fetal and the first years of life exposed to more risk factors, potentially affecting their development and later functioning, hence playing a role in their later risk profile of developing severe mental illness.
Fetal life and the first years of life are developmentally sensitive periods that form the basis for later mental health and vulnerability. Risk factors early in life affect brain structure i.e. the functioning of the brain, thus affecting cognitive, emotional, and social development and the risk for psychopathology later in life. Risk factors often occur in combination, not in isolation. Multiple, relative to single, risk exposures have more severe developmental consequences, and children are often faced with a constellation of risk factors rather than an isolated instance.
The impact of risks begins prenatally since the fetal brain has been shown to be influenced by risk factors such as e.g. maternal substance use, maternal use of medication and tobacco, and maternal stress. Postnatally, the first years of life represent a highly critical period for brain growth and development, with the potential to affect later adverse physical and mental health outcomes due to the enormous potential for learning, adapting, and changing that lies within early neurodevelopment. Known risk factors during early childhood include among others child-parent separation, insecure attachment patterns, insufficient parenting as well as the experience of stressful life events or severe trauma in early childhood for the primary caregiver or for the child.
Children born to parents with severe mental illness like schizophrenia or bipolar disorder, i.e. children with familial risk, are double vulnerable. Firstly, they have a genetic predisposition, not only for developing the same illness as their ill parent but also for developing other mental illnesses. Secondly, they have an increased likelihood of growing up in an environment with several of the risk factors that we know today. Further, children born to parents with schizophrenia or bipolar disorder are more likely to display early signs of vulnerability, e.g. emerging symptoms and/or developmental impairments themselves during childhood.
This was documented in our large population-based cohort study; The Danish High Risk and Resilience Study, where a cohort of 522 Danish children born to parents diagnosed with either schizophrenia or bipolar disorder were thoroughly investigated. We found that children from families with parental schizophrenia or bipolar disorder were exposed to a higher number of early risk factors, both during fetal life and in the first years of life compared with children from the control group. Pregnancies were more often unwanted and unplanned, the biological mothers more often took medication, drugs, and smoked cigarettes during pregnancy, and a higher number of stressful life events was reported during pregnancy. During the first years of life, children from families with parental schizophrenia spent more time with someone else than a biological parent, and children and primary caregivers experienced more stressful life events compared to our control group.
Moreover, we found a linear association between the number of early risk factors a child is facing in fetal life and the first years of life and the level of functioning at age seven. The more risk factors, the lower the level of functioning. Overall, children at familial high risk for schizophrenia or bipolar disorder displayed lower level of functioning and were facing more early risk factors indicating that familial high risk is a specific vulnerability marker. Importantly, the association between early risk factors and children’s level of functioning is not necessarily a causal influence and could be due to familial confounding effects.
Our findings are important as they reveal that on a group level, children born to parents diagnosed with schizophrenia or bipolar disorder already in fetal life and the first years of life are exposed to a higher number of risk factors, potentially affecting their development and later functioning, hence playing a role in their later risk profile of developing severe mental illness. Our findings contribute to the understanding that early interventions and preventive strategies must take their outset already in pre-pregnancy, be influential from birth, and during infancy and early childhood for families with parental mental illness to be beneficial for the development of these children. Targeting the parents with enhanced and specialized prenatal care including social support and support for good parenting could hopefully reduce perinatal risks and hence positively influence the developmental course of the offspring. □