People are considered "adults" when they turn 18, and given all the rights and responsibilities therein. But new research indicates our brains don't reach adulthood until we're much older -- and ignoring that could be damaging to young people.

Scientists used to think adolescence began around puberty and ended in our late teens when that physical growth ended. Today, though, researchers believe the brain doesn't reach full development until at least the age of 24, which means risk-taking behavior like drinking and drug consumption is fueled by hormones and a lack of self-control.

The number one cause of death among adolescents is an injury resulting from an accident often triggered by unnecessary or excessive risk-taking. In many states, understanding that has led to new laws including limiting how many other young people are allowed in the car with an underaged driver.

In addition, US researchers believe that heavy drinking during the teenage years before the brain is fully mature can affect the development of spatial memory (the ability to orientate oneself on a map and recall how to get from place to place), yet more than half of those with alcohol problems are diagnosed before the age of 25.

"Young people are our future assets," reads an editorial in the Lancet medical journal. "They provide energy, innovation, productivity and progress...Adolescent health [should be] an equal concern alongside existing health priorities in the world."

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