Child abuse from generation to generation: what role does the brain play?
‘We didn’t find any mechanisms in the brain for transmitting child abuse from generation to generation. What we did find is that experiences of neglect and abuse affect the brain differently,’ concludes Lisa van den Berg (Clinical Psychology). PhD defence 30 June.
‘Physical and emotional neglect are sadly very common,’ Lisa van den Berg comments. ‘But in practice less attention is paid to neglect than to abuse because it is difficult to trace. With neglect, you don’t receive the love, care or sensitivity you should be given, and that’s difficult to measure. Nonetheless, it’s important to look at the different subtypes of child abuse because they can have difference effects. This can influence the clinical treatment that’s needed, as well as the transmission of child abuse to the next generation.’
Van den Berg’s PhD research on ‘The Impact of Trauma’ is a broad study of the consequences of trauma, focusing on the role played by the brain in passing child abuse down through the generations. The biggest challenge was to find participants willing to talk about such sensitive issues as parenthood and abuse. Adults who have a higher risk of child abuse were invited to take part.
Van den Berg: ‘As well as asking participants themselves to take part, we also asked whether we could invite their family or partner. Besides the parents and children of the participants and their partners, we also looked at the horizontal line and asked adult siblings and their children to take part.’ In spite of the difficulties this research design might raise, fortunately many families were prepared to participate. Ultimately, we had 395 participants from 63 families, aged between 7 and 88 years in the 3G (three-generation) family study.
In the scanner
The participants came to the lab at the weekend for one or two whole days, in different groupings - with their own child and partner and also with the other generations – to carry out interaction and computer tasks, and an examination in the fMRI scanner. In the LUMC scanner, the participant’s brain was measured first at rest and then during different tasks. To measure the impact of experiences of child abuse and maltreatment on the brain, Van den Berg asked both the parents and their children questions about child abuse.
In the scanner, Van den Berg looked at how the brain responded to faces showing particular emotions and to the participant being excluded from a digital ball game. The question was whether the reactions to these tasks in the brain play a role in the transmission of abuse and neglect from one generation to the next. It made a difference whether the other players in the ball game were strangers or a family member, where the effects of being excluded seemed to go further than the context of the family. The reaction in the brain to facial expressions of emotions and to being excluded does not appear to be an explanatory mechanism for passing on child abuse.
As well as examining the effects of two computer tasks, Van den Berg also looked at the volume of the hippocampus, the part of the brain that is important for memory and the stress response. The question was whether differences in volume correlate with having experienced child abuse and abusive behaviour. Van den Berg: ‘We discovered that child abuse had an effect on the volume of the hippocampus, but did not find any link with maltreatment of your own children.’
Child abuse and neglect can lead to post-traumatic stress symptoms. But not all types of child abuse, for example emotional maltreatment and neglect, meet the DSM A1 trauma criterion needed for a diagnosis of post-traumatic stress syndrome. The same applies to other stressful life experiences. This prompted Van den Berg to also examine the impact of both traumatic and other stressful events on the occurrence of PTSS symptoms. She noted some differences between men and women. ‘Women develop equally severe symptoms after a serious traumatic event, known as an A1 event, as after other very stressful ‘non-A1’ events. Men, however, develop relatively more symptoms after ‘non-A1’ events. These are events that take place in the area of relationships, for example the death of someone who is close to you.’ Van den Berg therefore advises: ‘Look at people’s symptoms to make sure they don’t miss out on appropriate treatment or financial compensation via their health insurance. It’s also important to bear in mind differences between the sexes.’
What is the role of neuronal emotional reactivity in the intergenerational transmission of abuse? Read more about the 3Generation study: Stress and Emotions in a Family Context