Lucinda Coxon's Happy Now? has been attracting rave reviews in the national press and it is easy to see why. It is both immensely funny and painfully truthful, with scenes that make you wince with recognition. The action and the dialogue have a spontaneity and energy which work well on the stage and Thea Sharrock's directing is spot on.

Happy Now? portrays a group of have it all' middle-class high achievers whose lives are anything but fulfilled. At the centre of the play is Kitty, an overworked charity executive with two kids whose boss has cancer and whose father is in hospital with a life-threatening condition. Olivia Williams is brilliantly convincing as the beleaguered Kitty. Jonathan Cullen, who plays her well meaning but equally stressed-out husband, Johnny is also superb.

When Kitty is chatted up by another charity executive at a conference, her precariously balanced life becomes destabilised. The fantasy of temporary escape offered by the aging and out of shape Michael, played persuasively by Stanley Townsend, niggles away in Kitty's mind. The denouement towards the end of the play is subtly and imaginatively handled by Coxon.

Meanwhile the marriage of mismatched friends Miles and Bea is unravelling. Miles, Johnny's alcoholic ex-colleague, is full of acerbic wit. Dominic Rowan manages to be both engaging and exasperating in the role, and delivers his lines with perfect timing. Bea, his vacuous former PA (Emily Joyce), engages sympathy as she endures his cruel putdowns.

Kitty's gay friend Carl (Stuart McQuarrie) is her one source of support, but he is facing his own relationship challenges. Kitty's mother June is no help at all. Still angry with Kitty's father, who walked out on her 20 years before, she refuses to take his illness seriously. Ann Reid is hilarious as the attention-seeking and irritating June whose behaviour drives her daughter to distraction.

The action lurches from crisis to crisis and by the end of the play, as in life, nothing is resolved. The situations faced by the various characters are depicted with unnerving honesty and the dialogue is sharply observed.

The weakness of the piece is that it operates mostly at a surface level. Miles, Bea and Carl all have moments of self-awareness and insight. But Kitty and Jonathan perceive themselves only as victims of external forces over which they have no control. They have options but they don't see them. Nevertheless, there is much audiences will identify with in their predicament, and many of us have been there.

Happy Now? is at the Cottesloe Theatre until May 10. For tickets call 020 7452 3000 (www.nationaltheatre.org.uk)