Haunted Child, Royal Court Downstairs, London

The scintillating actor Ben Daniels is back on stage, with Sophie Okonedo (from The Slap), in an eagerly awaited premiere by Joe Penhall. This is the first play in four years from the author of Some Voices and Blue/Orange: portraits of mental illness that rang painfully true. Alas, though, Haunted Child, directed by Jeremy Herrin, proves peculiarly unconvincing.

Douglas (Daniels), an engineer unhinged, has gone missing from his terraced home in London. His wife, Okonedo's Julie, fears he is dead, but is trying to soothe their son, Thomas. The little boy claims he's seen Daddy in the night. Then Julie catches her husband prowling through the house looking like a dishevelled tramp, ghastly pale and with his front teeth missing.

Daniels and Okonedo have physically electrifying moments: tense, tender and desperate. But the dialogue seems stilted. Though he's avid when harping on about the scientific-yet-spiritual cult he has joined, it's cobblers nonetheless, with an unpersuasive pinch of Gothic horror. While aiming for sharp shifts between domestic naturalism, nightmarishness and satire, Herrin's production jolts around, falling short of all three.

What's unfeasible is Julie's behaviour. She listens to her spouse's spiel about "the Group" – a bunch of empirical vernacular Buddhists – and their guru whose esoteric thought course is the path to enlightenment. The Group also drilled into his gums, assured him the pain was psychosomatic, and took away his mobile.

And Julie's response? "How do I know you haven't just gone off and had a colossal nervous breakdown?" She doesn't call a doctor, or the police. She reckons some booze and sex will sort him out. Oh, and he can take Thomas to school in the morning.

By this point, one can't help wondering what planet she is supposed to be on and if the Royal Court has lost the plot. Still, let's get things in perspective. As Britain's most renowned new writing theatre, its 2011 main house premieres have been disappointing, not disastrous. This venue's running theme of screwed up ideologies has tapped into current anxieties, even if producing patchy, unfinessed plays. Here's hoping next year – with Roger Michell scheduled to direct another Penhall – sees the Court back on top form.

'Haunted Child' (020-7565 5000) to 14 Jan