Leave an extrovert alone for two minutes and he will reach for his cell phone. In contrast, after an hour or two of being socially on, we introverts need to turn off and recharge. My own formula is roughly two hours alone for every hour of socializing. This isn't antisocial. It isn't a sign of depression. It does not call for medication. For introverts, to be alone with our thoughts is as restorative as sleeping, as nourishing as eating. Our motto: I'm okay, you're okay-in small doses.