Think of a teenage brain like a car. That is, a car with very few miles on it and malfunctioning brakes.

The parts of our brain that regulate things like emotion and pleasure are large and in charge during our teenage years. But, the connections between these regions and the frontal lobe - which controls “executive functions” like impulse control and decision making - keep forming throughout our twenties.

“[The teenage years are] a time when you don’t have full access to your frontal lobe,” says Dr. Frances Jensen, author of The Teenage Brain: A Neuroscientist's Survival Guide to Raising Adolescents and Young Adults. “But - fortunately, or unfortunately – you’ve got full access of the emotional areas of your brain. We do see that teenagers have greater challenges controlling their impulses, controlling emotional ability, and are very, very susceptible to peer pressure… without that frontal lobe to say ‘bad idea.’”

During this time, teens’ brains are also developing new synapses, or connections between brain cells, much faster than adults. This allows them to learn new ideas and skills very quickly. But it can also lead to problems with addiction.

“Addiction is simply another form of learning,” explains Jensen. “It’s just happening at a different part of your brain.”

Teens’ lack of impulse control also puts them at greater risk for trying drugs or alcohol. And when coupled with their still-forming synapses, this impulsivity can lead to much higher rates of drug addiction. “Teenagers can be addicted faster, harder, longer, stronger than adults,” warns Jensen.

Adolescent brain chemistry also explains teenagers’ penchant for staying up into the wee hours of the night – and why it’s so tough to roust them for school early in the morning. Teens’ brains tend to release melatonin - the chemical that tells our body that it’s time to go to sleep - several hours later than most adult brains.

“When you wake up a kid up at six or seven in the morning to get on a bus, that’s like waking an adult up at three a.m.,” Jensen says. “So we risk chronic sleep deprivation. We may want to think about what the brain can actually do when it’s trying really hard to wake itself up. Maybe that’s not the time to start the SATs, at eight o’clock in the morning.”

Jensen hopes that her research will help parents better understand the habits of their rebellious, impulsive and sleep-deprived teens.

“Adults will look at a teenager and they’ll get really annoyed,” she says. “They’ll transpose their own value system and their own ability to control their impulses onto the teenager, and it's just not going to happen.... It’s the biology that they have.”