The adolescent brain: beyond raging hormones.  Neuroscience research is suggesting some reasons why teenagers are that way.
D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D010379:Peer Group; D000297:Psychology, Adolescent; D012309:Risk-Taking