In the standard “things are worse now than ever before” polemic, it's claimed that rates of mental illness are higher now than ever – usually without any proof, and usually alongside known-false claims such as people now being more violent or less healthy (compared to, say, the 1400s).
It seems clear that rates of diagnosis are on the rise, as are disability claims. But can't this just be due to lowered thresholds for diagnosis, and more people seeking treatment? Are there studies that show incidence actually increasing, or an upward trend in psychiatric assessment scores?
Although I've heard this most often amid a laundry list of unsourced (mostly known-false) claims, here's an article in Spring 2005's Ethical Human Psychology and Psychiatry which was later expanded into the book discussed here. It claims that mental illness per 1000 went from 0.2 in 1850 to 20 in 2003.
What I'm looking for in an answer is:
- Historic prevalences of a few mental disorders with very well-defined symptoms,
- A good proxy for mental health (e.g., attempted suicide) over at least 50 years, or
- Repeated applications of a psychiatric assessment scale to groups of people “picked up off the street” at intervals over a total of 25 years or more (not a cohort study; a different group every time).