In 1977, Tom Stoppard and Andre Previn delivered a multi-media production called Every Good Boy Deserves Favour. Because the production requires an orchestar and cast of actors, it is rarely performed.
Here's the synopsis from Wikipedia:
The play concerns a dissident, Alexander Ivanov, who is imprisoned in a Soviet mental hospital, from which he will not be released until he admits that his statements against the government were caused by a (non-existent) mental disorder.
In the hospital he shares a cell with a genuinely disturbed schizophrenic, also called Ivanov, who believes himself to have a symphony orchestra under his command. Alexander receives visits from the Doctor and from a Colonel in the KGB.
Meanwhile, his son, Sacha, is seen in a school classroom with a teacher who attempts to convince him of the genuineness of his father's illness.
Great news: The National Theatre (London) is mounting a production that's scheduled to hit the boards next year. Here's the story that tipped me off [link].