Nicotine is the addictive chemical in tobacco smoke and e-cigarettes vapors. Nicotine can reach the brain within seven seconds of puffing on a cigar, hookah, cigarette, or electronic cigarette. Nicotine acts like a key that unlocks special receptor molecules on the outside of the cell in the brain, including those in the prefrontal cortex.
The brains of teens who smoke or vape may create more receptors to handle the flood of nicotine they have come to expect. As the number of receptors increases, teens will need more nicotine to get the same high. That makes nicotine users seek hit after hit.
Exposing the developing adolescent brain to nicotine "could lead to a high risk of lifelong addiction," says Garry Sigman. The nicotine can make it hard for them to stay focused. It might also trigger bouts of depression or anxiety.