Theroux spends a lot of his time visiting America as a smug pom whose dry sense of humour completely escapes the people he is sending up. His 2016 brain injury documentary was superb.
In a BBC2 documentary A Different Brain, Theroux visited residential patients in a brain injury unit. Many had completely changed personalities and through loss of inhibition, aggression and other impairments to their judgement were incapable of caring for themselves in the community.
One particular lady was totally friendly to anyone she met without any sense of wariness of strangers. When Theroux left that patient, he said to the doctor who was accompanying him quite rightly that unscrupulous people would take advantage of her the moment she left the brain injury facility. That hit the nail on the button as to why these people must stay in care.
Then he moved on to a particularly heart tugging session where a mother found that her son’s body was inhabited by a complete stranger. The brain injury are totally changed his personality and turned him into a completely different person but she stood by her son.
Another one of the patients he followed also had a major personality change and was rude to her family, so much so that they did not want want her to live with them. She had no awareness of her change in personality or the fact that she was infuriating her family with her behaviour. They try from time to time to bring her back into the home but it does not work.