Professor Sallie Baxendale

Professor Sallie Baxendale, Consultant Clinical Neuropsychologist at University College Hospital London and a Professor of Clinical Neuropsychology at UCL, writes about the importance of adolescence for the development of the teenage brain, and the risks of puberty blockers.

My expertise lies in neurodevelopment and way that the brain develops.  

Adolescence is a time of significant rewiring of the neuronal connections that were made in childhood, a process that is triggered and fuelled by the hormonal changes that occur during this time. The hormones released during adolescence don’t just trigger the development of secondary sex characteristics, they set off a whole cascade of changes in the way different parts of the brain are connected.  

Studies have shown that teenagers make decisions in very different ways to both children and adults whilst this rewiring process is going on. Adults think with the prefrontal cortex, the brain’s rational part. This is the part of the brain that responds to situations with rational judgment and an awareness of long-term consequences. However, teenagers tend to process information with the the emotional part of their brain. In teenagers’ brains, the connections between the emotional part of the brain and the decision-making centre are still developing—and not always at the same rate. That’s why when teens have overwhelming emotional input, they can’t explain later what they were thinking. They don’t think so much as feel.  

In addition to prioritising feelings over facts, brain imaging studies have also shown us that teenagers assess risk in different ways from both younger children and adults. Many of the choices teenagers make carry consequences that unfold over the course of their adult lives. The ability to accurately ‘value’ an outcome in the future, attached to a decision taken today requires a complex network to develop within the brain, a process that isn’t complete until adulthood. Whilst these connections are being established, teenagers are not good at judging the ‘value’ of likely outcomes in the future, particularly if they are far in the future and outside their experience to date.  

Studies have shown that in situations where consequences are immediate and direct, adolescents are less influenced by their explicit knowledge of the probabilities of potential negative outcomes, and are more willing to take risks to obtain potential rewards. The influence of peers is another uniquely powerful factor that impacts decision making in teenagers. Adolescence is a period of life in which peer relationships become increasingly important. This appears to be hard wired.  Studies have found that young adolescents are more strongly influenced by other teenagers than adults when it comes to the assessment of risk. For early adolescents, the opinions of other teenagers about risk matter more than the opinions of adults.  

Neuroscience has much to tell us about the adolescent brain and the way in which teenagers understand the world and make decisions. I am very concerned that a Conversion Bill that includes clinical input will not allow the robust and challenging conversations that are required to ensure young people are giving informed consent for medical treatments which may have a long term, irrevocable impact on their lives as adults. Failure to have the conversations which take the neurodevelopment context of the patient into account, will end up harming rather than helping young people struggling with their gender identity.