"Impulsive behavior occurs when too much value is placed on immediate pleasure and not enough in long-term consequences," he says. "When you do things that support your evolutionary survival, eating when you're hungry, drinking when you're thirsty, having sex to reproduce the species, your brain rewards you with a hit of dopamine." The reason why drugs are so dangerous is because they give an enormous hit of dopamine,. We write in the book, they're like a guided missile that hits the dopamine center of the brain with a chemical blast.," author writes.