The Cottesloe has been transformed into a medical centre and reception area, with some immensely comfortable new beige banquettes - can we keep those, please? - for ENRON author Lucy Prebble’s new play about analysing the behaviour of drug-taking volunteers in a commercial scheme investigating the causes of depression.

Depression, of course, can be caused by plays about depression, and I’m not sure whether Prebble is exposing a drugs company scandal in the fields of neuroscience and psychiatry or whether she’s writing an unusual love story between Billie Piper's depressed and wounded Connie, a university psychology student, and Jonjo O'Neill's hyper, frenzied Tristan, who just happen to share the same birthday.

She’s doing both, really, and Rupert Goold's characteristically bravura staging, a co-production between the National and his Headlong touring company, played out on beds, tables and the open carpet of a fictional drugs company, Rauschen, shows that there’s no drug like sexual energy to combat depression; and that the two “triallists” are utter mugs, toyed with by the doctors, who double-dose, double-bluff, and downright deceive their frisky guinea pigs.

Our banquettes tremble along with the undercurrent of sound provided by Christopher Shutt, while Miriam Buether’s design creates an antiseptic environment that is resisted only when Tris leads Connie next door to an old asylum with tiled floors and goes into an amazing tap and soft shoe shuffle to "I've Got You Under my Skin".

In the second act it becomes clear that satire is not enough. A sinister Big Brother element of “who’s testing who” comes into play, with the rather pat unravelling of a former relationship between the testing doctor, Lorna (a performance of, well, neurasthenic intensity from Anastasia Hille), and her psychiatric superior, Toby (played with a sporting and arrogant flourish by Tim Goodman-Hill).

Very cleverly, the play becomes an anti-romantic comedy of parallel friendships, the first one forged in the hothouse of dodgy experimentation, the other leaving a trail of emotional disintegration and loneliness in its wake; the woman’s loneliness, that is.

I’m not sure how the play, as a logical structure, survives the flaunting of the isolation rules when Connie and Tris follow their out-of-bounds escape with an explicit dance of lust and copulation on their adjacent beds, but the dramatic point is that the drugs aren’t working.

Piper gets better every time I see her, and this performance is full of laughter and tears, great physical verve and vivacity, while O’Neill burns up the stage with an electrifying confidence and swagger burnished in his RSC work over the past few years. An imperfect play, maybe, but one that pleases and provokes in equal measure.