Disappearing Friends (Norwich)

Hamilton Wilson's Disappearing Friends is about living with dementia. It's a Hostry Festival co-commission and suffers, like any other piece of special pleading, by placing before us four people who are two-dimensional types rather than rounded characterisations.

They are houswife Ellie (Mel Sessions), Stuart her husband now launched into retirement (Peter Sessions), their daughter Jenny (Tracie Harris) and her husband Rob (Joe Nemeth). Ellie has been suffering from memory loss, what Jenny jokingly describes as "senior citizen moments".

It is of course more serious than that. Over four scenes we are shown how it is not just Ellie who is affected by Alzheimer's; walking in the park with her daughter, Ellie recalls the formal and colloquial names of the different flowers but mistakes passing strangers for intruders in to her own much-loved garden.

Stuart meanwhile has to cope with being a carer while watching the woman he has loved for so many decades morph into someone else. And that's not to mention the bureaucratic hurdles of medical and social services' understanding, support and treatment.

Director Tom O'Sullivan punctuates his production with interludes in which specialists in the various disciplines involved in dementia diagnosis and treatment. This allows the dramatised story to be, for an uncommitted audience member, unduly diluted.

You can preach a sermon – be that social, religious, political or even medical – and not leave the audience feeling "got at". The medieval mystery and morality play scripters did it. Nearer our own time so did Davids Edgar and Hare as well as Peter Nichols with A Day in the Death of Joe Egg.

Disappearing Friends takes a serious subject and treats it seriously. But, for me at any rate, it doesn't work as well as it might. or indeed, should.