Burn/Chatroom/Citizenship, National Theatre: Cottesloe, London

William, a super-bright, if damaged and destructive, teenager in Enda Walsh's Chatroom, argues that JK Rowling is "the enemy" and should be "taken out". She's the kind of children's writer who sees young people as a threat and plies them with fantasy fiction to stop them thinking for themselves.

I should imagine that William would pooh-pooh most upmarket writing for teenagers as the continuation of condescending social work by other means. I think, though, that these plays would defuse even his cynicism. They don't suck up, talk down or preach. They are neither anthropological investigations, nor exercises in presumptuous empathy. Rather, the dramatists seem to combine close knowledge of contemporary teenagers with the ability to tap into that part of themselves that will be permanently 15 and insecure.

The most enjoyable of the bunch is Mark Ravenhill's Citizenship. Tom (Sid Smith) has had an erotic dream about French-kissing someone. The only problem is that he doesn't know whether it was a woman or a man. The play whisks him around various ports of call in his quest to clarify his sexual identity. There's a funny portrait of a young gay teacher (Richard Dempsey) who is too stressed and racked with professional caution to respond to Tom's flirty appeals for help. Matt Smith is hilarious as "Gay Gary", a white pupil who smokes joints and talks like a stoned black man and who, as his website graphically proves, is not as his nickname suggests.

Self-harming, drug-taking, teenage pregnancies: they are taken for granted in the world presented here. "I'm unhappy - too many choices. You were unhappy - no choices. Everyone's unhappy. Life's shit, isn't it, sir?" says Tom when, in a fantasy moment, the teacher pops up through a trapdoor, just as our hero is about to bed a female classmate. But there's a wonderful comic resilience in the writing that belies this pessimism, as does the ending, which implies that Tom won't settle for a loveless life of "money, sex and fun".

The manipulation and bullying possible in teenage chatrooms is the subject of Enda Walsh's worrying play, which shows how a couple of bored adolescents try to talk a vulnerable youth into suicide. This latter is superbly played by Andrew Garfield, who also makes an indelible impression as the sensitive loner Birdman in Burn, Deborah Gearing's poetic story of the last day in the life of this frustrated and intuitive teenager.

In rep to 3 June (020-7452 3000; www.nationaltheatre.org.uk)