Gender Specific Changes to the Brain Influence Psychiatric Risk

Scientists have determined that blood flow in the brain starts to differ between boys and girls once they hit puberty. This might explain why gender appears to play a role in susceptibility to certain psychiatric disorders, a new study suggests.

The study, published in the Proceedings of the National Academy of Science, details how puberty is an important moment for the brain structure of a person, and how this stage can change how susceptible the mind is to many different kinds of mental disorders and their varied symptoms.

According to the study, as a child's brain develops, brain blood flow gradually decreases at a regular rate that is no different between boys and girls. However, once a child hits puberty, this cerebral blood flow (CBF) level undergoes sudden and drastic changes. Female brain CBF levels experience a sharp increase, while males suffer further decline.

Researchers determined that the brain undergoes such massive sex-specific changes during puberty after taking arterial spin labeled magnetic resonance images (MRI) of the brains of over 900 young people, between the ages of 8 and 22 years old.

They found that, on-average, blood flow levels diverged according to gender around age 16, which is mid-to-late puberty for most. More importantly, they found that by the end of adolescence, most females had markedly higher CBF levels in parts of the brain involved in social behavior and emotion regulation - which may explain why adolescent girls appear to be more susceptible to certain social anxiety conditions, compared to their male counterparts. However, some experts have previously argued that differences in gender social standards simply make male versions of these same disorders less commonly reported.

"We know that adult women have higher blood flow than men, but it was not clear when that difference began," Theodore D. Satterthwaite, MD, MA, said in a recent press release, explaining that the data could be invaluable for monitoring mental health.

"These findings help us understand normal neurodevelopment and could be a step towards creating normal 'growth charts' for brain development in kids," he added. "Hopefully, one day such growth charts might allow us to identify abnormal brain development much earlier before it leads to major mental illness."

The study was published in the Proceedings of the National Academy of Science on May 27.