“People are capable of anything, that’s what I’ve learned.” So says the big, troubled security guard that David Morrissey plays in Neil LaBute’s three-hander. And so audiences have regularly learnt from an American dramatist whose characters have gone smilingly from a posh party to beat cottaging gay men to smithereens, or tossed babies to drown in swimming pools, or, oh, done lots of ugly, evil things.

The insight at the core of In a Dark Dark House is maybe the most disturbing of all. A man may be abused and enjoy the experience. He may be damaged and have been complicit in the damage. He may have loved and may still love the person who has ruined the rest of his life. The final accusation to be made against child abusers is that they steal hearts as well as hurt bodies and warp minds.

It’s hard to tell you how LaBute reaches this conclusion without giving away the essentials of a play that consists of the gradual revelation of intimate secrets. Unless you’re very innocent, you’ll guess why Steven Mackintosh’s Drew, a disbarred lawyer famous in his family and probably elsewhere for his habitual lying, has crash-landed in alcoholic rehab. You don’t have to be a shrink to suspect that his elder brother, Morrissey’s Terry, trails a similar past. Terry was additionally tormented by a violent father, but both men were sexually abused in childhood by a family friend called Todd Astin. With the brothers edgily circling each other, and the odd emotional explosion interrupting their awkward parley, the play takes time getting going. You see that Drew’s adolescent lingo (“hey, dude”) tells a psychological truth, but you wish LaBute wouldn’t labour the point. I initially thought Morrissey’s acting a bit stiff, almost as if he was waiting for his cues rather than reacting instantaneously to their content, only to find him more and more impressive as Michael Attenborough’s production proceeded. The last of the play’s three scenes, with that stiffness revealed as insecurity and a wary defensiveness and Mackintosh’s small, scrawny Drew sharing his increasingly evident pain, is all-American in its energy if not quite in its accents.

Before that comes a scene that’s a slight cheat, since it generates spurious tension, inviting you to think that Terry may take sexual revenge on Kira Sternbach as Astin’s teenage daughter, Jennifer, only to learn subsequently that revenge isn’t at all on his mind. I’d better say no more, only cavil at Lez Brotherston’s set, which could be darker, more ominous, more in keeping with a title whose full meaning becomes clear when you read LaBute’s programme note. Like Terry, who was regularly and vindictively beaten by a parent he hated and once almost killed, the dramatist had to escape a father “who scared me much of the time and whose quicksilver moods moved from euphoric highs to shattering lows”. Like Terry, he . . . – but go and see this very personal, pretty powerful addition to the LaBute files.

Box office: 020-7359 4404, to January 17

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