Be wary, very wary, of plays in which actors step out of their roles to apologise for the confusions of the narrative, or the narrator admits that the piece isn’t quite right, or things become self-consciously meta-theatrical or whatever the in-word is. All this occurs in Lisa Kron’s autobiographical Well. Though the effect can be enervating, there are reasons for the chaos.

Kron is an American writer who has often appeared in her own solo plays, and Well is, we’re told in a paradox typical of the evening, a “a solo performance but with other people in it”. It also aspires to be what Natalie Casey, who plays Kron, self-mockingly calls “a multi-character theatrical exploration of issues of health and illness both in the individual and in the community”. The result is a show in which Kron describes what it’s like to belong to a health-obsessed Midwestern family and herself to have spent time in a Chicago “allergy unit” - but one that’s persistently interrupted by Sarah Miles as Ann, her bedridden mother.

Casey is sometimes emotionally authentic, sometimes disconcertingly shrill as her Lisa tries to cope with Miles’s gleeful, cackling, truculent, overbearing Ann. The daughter threw off sickness, moved to New York and says that she lives a healthy, fulfilling life there. The mother went through a reverse process. Reeling from an upbringing in racially divided Baltimore, Ann found health and fulfilment in promoting integration, only to succumb to illness after illness, disintegration after disintegration. Why, she even boasts of having had mono-nucleosis, which you can supposedly have only once, no fewer than six times.

Helped by a darkly comical scene in that Chicago ward, the play vestigially does what it claims: which is to ask how much, how far sickness is wanted, willed, or subtly welcomed by the patient. As a recovering hypochondriac myself, I’d have liked to have heard Kron do more to argue her case, which seems to be that pain can be both horribly genuine and mediated by the mind. But the play’s emotional centre is her relationship with a mother who craves attention. In one of its more Pirandellian moments all the supporting actors in Eve Leigh’s production fall for this maddening, charismatic woman and reject Lisa as “manipulative and wrong”.

Where does that leave us in the audience? Damned if I know. Damned if Lisa Kron knows. But that’s surely the point. Mums and mumps are equally befuddling, equally mysterious. A truth or a truism? This bold, uneven play leaves me still deciding which.

Box office: 0844 4124658, to Jan 24

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