What happens in a family that has no “cultural capital”? If it lacks the education and knowledge to make sense of the world; if it lacks the emotional skills to manage its internal relationships; if it is not so much dysfunctional as non-functional, what will happen to its members? Sam Shepherd’s 1985 A Lie of the Mind explores this question, through two families that are widely separated in geography – Montana and southern California, but joined by their joint hopelessness and haplessness.

There are no obvious clues in this production as to why the winner of the JMK Award 2006 for Young Directors, Jamie Harper, chose this as the award show, but given the current state of America, and its bemused, confused, baffled blundering around the international stage, it is hard not to read it as metaphor. But if this was intended, some clues should have been provided.

But perhaps this production is instead just meant as a portrait of human self-destruction and mental collapse. It certainly does that powerfully – perhaps too powerful for the intimate space of the BAC. I know that domestic violence is a terrible thing, but having its victim very nearly in my lap, pathetically sobbing for the man who gave her brain damage, is perhaps setting the emotional volume rather too high.

The play opens with a near-hysterical Frankie (Rob Wynn) on the phone to his saner brother Jake (David Caves). A classic domestic abuser with a long chain of violence behind him, he believes that he’s killed his wife Beth (Emily Hamilton), but in fact she’s in hospital, being cared for by her brother Mike (Simon Harrison), who has the matching role to Jake – the family’s sane one.

But as parents arrive on the scene — Jake’s near-incestual mother Lorraine (Pearl Marsland) and brittle sister Sally (Nadia Albina); Beth’s hunting-obsessed father Baylor (John Joyce) and psychologically abused mother Meg (Cara Chase) — even the sane ones fall to pieces – slowly, very slowly. Three hours (with interval) is a long time to watch this collapse, and the lighter moments are few and far between. It sometimes feels as though you are watching a Channel Four documentary about social work – one that the PR person would have called “hard-hitting”.

There’s nothing much wrong with the acting – Wynn is a powerful, tormented Frankie who never slides into melodrama; Hamilton manages the Alzheimer’s-like switches between dangerously clear lucidity and outright inanity well; Marsland is creatively unbalanced in the way of the truly psychotic. The staging is interesting too, with the two opposing family sets on opposite diagonals between the audience, although the lighting arrangement becomes intrusive as the shadows cross and confuse from each side.

The level of intellect of the characters makes for the obvious in dialogue. “It is deer season. In deer season you hunt deer,” Baylor says, when asked to explain the physical torment to which he’s subjecting itself. In the end I left this production feeling that it had an equally simple message: “There is terrible suffering. You will watch this terrible suffering.”

The theatre, with online booking. The production continues until August 6. The Guardian’s view.