New study reveals impact of childhood trauma on brain structure

Psychotic experiences, such as delusions and hallucinations, are prevalent in 5-10% of the general population and not just people with diagnosed serious mental illness such as schizophrenia. Previous research has shown that adverse experiences increase the risk of developing psychosis, but how and where these experiences impact on the developing brain is unclear.

This study, led by Dr Kate Merritt (UCL Psychiatry) and involving researchers from UCL, in collaboration with the University of Bristol and Cardiff University, investigated two specific environmental risk factors – birth complications and childhood trauma – and looked at how they affect brain structure.

Complications during a mother’s pregnancy and birth can increase the risk of a child developing psychosis later in life by around 1.5 times, while psychological trauma experienced during childhood can increase the risk of developing psychosis by three times.

The findings, published in Molecular Psychiatry, show that people who experience childhood trauma or pre/perinatal complications are more likely to have smaller volumes of a region of the brain called the insula, and a larger region called the striatum.

This may be relevant to the development of schizophrenia, as independent research finds that these brain regions are also altered in schizophrenia patients. The insula is responsible for emotion processing and mood regulation, often disturbed in psychiatric disorders, and its smaller volume may explain the link between these risk factors and the increased likelihood of developing a mental health problem. The striatum is responsible for detecting threats. Its larger size in those experiencing trauma may represent adaptive changes to the threatening environments individuals have endured through childhood. 

The researchers looked at over 400 detailed brain scans from people in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, the largest UK birth cohort dedicated to examining mental and physical health. Between April 1991 and December 1992, ALSPAC recruited approximately 14,500 pregnant women, and has been following the health and development of the children ever since.

This study shows that the build up of risk factors, rather than experiencing one risk factor alone, is associated with changes in brain structure. For example, brain changes were seen in those who experienced multiple types of childhood trauma, including physical cruelty, domestic violence, sexual abuse, emotional neglect, emotional cruelty and bullying. For the pre and perinatal risk category, 16 categories were examined, including whether the birth was premature, birth weight, birth length, paternal and maternal age, and whether the baby had breathing difficulties. Similarly, one risk factor alone was not associated with brain changes, but the accumulation of pre and perinatal risk factors showed an impact on the brain. These findings suggest that preventative interventions should aim to help people who have experienced multiple risk factors in their environment.

Dr Merritt said:  
"We know that a difficult start in life increases the risk of developing later mental health disorders, and our study shows that this may in part be due to the effects of the environment on the brain, particularly in brain regions responsible for fear and emotion processing."

Related

• Read the paper in Molecular Psychiatry
• Dr Kate Merritt’s academic profile
• Dr Anthony David’s academic profile
• The UCL Division of Psychiatry
• The UCL Institute of Mental Health
• Avon Longitudinal Study of Parents and Children (ALSPAC)