Jonathan Miller, the writer and host, is a polymath, an MD who is best known for his staging of opera and his TV presentations. He has a smooth, earnest, and convincing delivery, which is okay because he knows what he's talking about.
His approach to the subject isn't academic at all. It's a little historical, with one extended case history illustrating the battle of wits in the 1600s over whether madness was the result of some natural malfunction or witchcraft. It's not exactly about the evolution of treatment methods either. Pinel doesn't get to release the patients from their chains at La Bicetre hospital. If you're interested in how "loonies" were treated in Mozart's time, let me recommend two above average feature films: "The Madness of King George" and Val Lewton's "Bedlam."
Instead of following one theme (eg., schizophrenia) or one hero (eg., Freud), this program is a kind of scattershot overview of a problem that about ten percent of us will experience in some form in our lifetimes.
What's missing? Well, the American Psychiatric Association's DSM lists all the forms of mental illness known to Western man. After some recent events in the political arena, I've begun to wonder if the the social psychologists shouldn't develop a similar handbook covering the madness of crowds. The last hundred years should have demonstrated that crowds, or whole nations, can be far more puzzling and dangerous than one insane individual.