I remember the US L&O episode that this one was based on, and the American actor who played the schizophrenic was Denis O'Hare (True Blood viewers may recognise the name). He was brilliant, and I'm happy to say that Rupert Graves was very very good as John Smith as well. I'm surprised that the scripts have so few changes from the US ep they are based on, and that they even keep the names of the characters the same.