Bigger is not necessarily better when it comes to the ‘tail’ of a teenager’s brain, researchers at the University of the Sunshine Coast have found.

In a study published in Brain Research, the team from USC’s Thompson Institute discovered that when a part of the brain called the caudate measured smaller, it was linked to greater wellbeing, such as optimism and resilience to future stress.

The team assessed 49 12-year-olds enrolled in the Longitudinal Adolescent Brain Study (LABS) and found significant relationships between participant responses on a self-reported wellbeing questionnaire with brain structure measurements from MRI scans.

Lead author Ms Amanda Boyes said the findings could one day help provide neurological biomarkers to inform mental health interventions or preventative programs for a critical point in adolescence.

“What this means is that bigger is not necessarily better when it comes to the size of the caudate in adolescents,” Ms Boyes said.

“The caudate links the executive function regions to the emotion processing regions of the brain. It has been associated with movement, motivation and reward and there may be something here that differentiates between people reporting higher levels of wellbeing earlier.

“The fact that a smaller caudate is linked to greater wellbeing might mean that this particular area of the brain has become more efficient early on, but we still need to do further research to understand why.”

The caudate is located in the basal ganglia in the center of the brain. It is long and curved and wraps around the sub-cortical parts of the brain, which is why it is named after the Latin word for ‘tail’.

A short explainer video is here.

Study supervisor Professor Daniel Hermens, who leads LABS, said adolescence was a critical time to identify mental health issues, as onset of problems at this stage could last well into adulthood.

“The 12-year-olds coming into our study are at a crucial time in their lives for detection and intervention of mental health problems,” Professor Hermens said.

“And yet despite this, youth mental health is still one of the most under-studied areas of mental health.

“Considering the rising number of cases, it’s vital that we are looking for biomarkers in the brain like this that could inform youth wellbeing programs and interventions.

“If we know more about the unique characteristics of the brain that might be linked to mental health conditions, we might have better responses to the negative impacts, and could reduce the severity of mental health problems long into adulthood.”

Other focuses of LABS include youth anxiety and attention, cyberbullying and COVID impacts on youth levels of worry over time.