My teenage son rarely gets out of bed. he's not always sleeping. but he seems very lethargic. is this normal?

Quite obviously not: It may surprise you to know that a profligate diet might be the cause or perhaps even drugs. You should get him checked out for it is serious.

Several possibilites: Teens do sleep a lot. However several things may be going on. He may be sleep phase shifted- staying up all night with computer/video games and sleeping during the day. He might be depressed or using alcohol and/or drugs. Very important to have him see his physician as soon as possible. He can be evaluated for sleep disorder and other issues.

Teenager: I would recommend having him seen by family physician to check his health status & do blood work, also rule out illicit substance use.