Of all the social prejudices that remain to be breached, mental illness is stubbornly isolated.
The war may not yet be won for LGBT but for those with mental health problems seeking support, understanding and acceptance, it has barely begun.
Brave then, for a new play by Deborah Bruce to tackle the issue head-on - and for conservative Chichester to give it its world premiere.
From the start, the production pricks our sensibilities. Are we laughing with the brother and sister reclusively trapped in the family home - or at them?
Aren’t the piles of old newspapers and junk and the hedges overspilling on to the London pavement just a little too stereotypical?
And isn’t there a two-dimensional naivety in the scripting about those from outside - the neighbour who wants to buy the house at a knock-down price exploiting their vulnerability and the newspaper photographer whose shameless lack of professional introduction would never be tolerated by editors or their regulator today?
In the midst of it all, an allegation of child abuse made against the aging brother is a story-line which is as uncomfortable as it is predictable.
Ignore all these potential short-comings.
Thanks to a breathtakingly brilliant piece of mesmerizing acting by Samantha Spiro as sister Peppy, this play is transformational.
Just when you think the story has failed to deliver it rises right above itself to surprise, to shock and to bring the audience shoulder to shoulder with Peppy and her equally supremely cast brother Daniel (Daniel Ryan).
We haven’t seen a performance approaching Spiro’s assured excellence at the Minerva since Zoë Wanamaker dazzled there in 2014 in a portrait of poet Stevie Smith.
Worth noting a stand-out performance from Rudi Millard.
In the end, there is plenty of laughter. All of it with the cast and none of it directed at them. There are tears too. Whenever an audience is challenged and brought safely to a new perspective with compassion and good humour there is always an emotional outburst.
It’s clear now, that the first few performances of Daniel Evans’ first season here was merely a taxi-ing down the runway. The engines are now roaring and the great machine that is the festival theatre is in full flight - soaring above the city and doing cartwheels in the sky.