better ways to feel more alert, quitting the stuff can leave you with days of severe headaches and possibly the jitters from withdrawal. (Cutting back slowly, by half a cup a day, can help lessen those effects.)

In addition to increased caffeine use, sleep deprivation can also result in increased use of alcohol, nicotine, and other dangerous substances. Teens who are too tired to exercise, stressed from arguments with parents or friends, worried about keeping up in class, or just generally feeling down about how they look or feel may turn to alcohol or other drugs to cope or to ease the pain. On their own, all of these substances are, of course, addictive and bad for your health and safety. But using them when you’re sleepy heightens their effect. Studies show that impairments that result from combining drugs with sleep deprivation are greater than those that result from each alone.

If you’ve read through most of this chapter, you probably won’t be surprised that a sleep-deprived teen might have some problems with interpersonal relationships. Most likely you’ve seen that effect for yourself, not only in your own relationship with your child but in her relationships with friends and other family members. Just being an adolescent can make developing and sustaining relationships difficult; adolescents’ strong emotions and volatility can cause ruptures with friends and arguments with family. But an exhausted teen has even fewer resources for staying on an even keel with pals and loved ones.

Sleep-deprived teens have less patience to see things through. So if they have words with a friend, they might not be able to wait until the blowup simmers down. Being irritable and edgy can provoke them to act immediately and unreasonably—and perhaps cause them to lose a friend.

Being constantly tired can also cause teens to miss school and activities. Along with losing class and learning time and perhaps exercise