The Invisible Plague

You know it is a book by a non-professional writer when, by the end, you get no "closure." Dr. Torrey has made a pretty convincing case for his theory that the prevalence of insanity --- namely severe mental illnesses involving psychosis, particularly schizophrenia and bipolar disorders with psychotic features --- has been rising slowly but steadily in the past three centuries. Chapter after chapter, he cited historical evidence ranging from hospital records and case documents to artistic depiction and public fascination with insanity to prove that, in four countries with fairly credible historical records (England, Ireland, Canada, US), the rate of insanity has risen from about 1 in 1,000 adults, equivalent to about 0.5 per 1,000 total population, in early eighteenth century to about 5 per 1,000 total population now.

I had never heard of this claim until I met him recently for the story about toxoplasma. OK, so I'm neither a physician nor a historian, but I consider myself better read in medicine and psychiatry than most lay people. This smells like fringe stuff. Yet, he certainly does not sound like a fringe-minded person. In fact, the book is extensively and meticulously referenced and appears to lack over-generalization and over-arching conclusions that I've become sensitized to in recent years (thanks to some very popular "scientific" writers).

One of the deductions that sort of convinced me is this: We all know that certain diseases can cause psychosis ---- syphilis, leprosy, and various other infections that enter the brain; malnutrition (especially severe vitamin B deficiency); traumatic brain injury (e.g., James Hadfield who attempted to assassinate King George III got his brain injury in a war); brain tumors; etc. Even an idiot (another word forbidden not only by psychiatrists but also by respectable media) knows that infections, malnutrition, and brain injury from wars have significantly declined in the past 300 years, certainly in the past 60 years. Yet, the incidence and prevalence of insanity have not benefited from the general improvement in our living condition. Hmm.

Torrey noted only in an appendix that the rise of the insanity epidemic since mid-eighteenth century coincides with the widespread practice of adopting cats as pets. He fully acknowledged that this epidemic temporally aligns with industrialization and urbanization (except in Ireland). A decade after the book's publication, he seems more convinced now that cats have something to do with it after all.

So what's the answer? What the hell causes insanity and continues to cause insanity to this day? All I can say is nobody knows. The availability of drugs to treat this and that mental disorder might give the public a feeling that doctors know what they are doing, but in reality ...