I’ve happened upon an interesting snippet from the regular Nature “100 years ago” feature concerning a 1907 debate on whether insanity was really increasing or whether it just seemed that way due to changes in diagnosis and treatment methods.
It made me smile because it is almost exactly the same argument that is being had now about whether cases of autism are genuinely increasing or whether this just reflects changes in diagnosis and treatment methods:
Notwithstanding the much improved statistics recently issued by the Lunacy Commissioners, thoroughly satisfactory materials are still wanting for solving the question whether the prevalence of insanity is or is not increasing. The importance of the problem… imparts special interest to a paper by Mr. Noel A. Humphreys on the alleged increase of insanity… This paper shows in a striking manner the value of scientific statistics in checking crude figures.
The author expresses a decided opinion that there is no absolute proof of actual increase of occurring insanity in England and Wales, and that the continued increase in the number and proportion of the registered and certified insane is due to changes in the degree and nature of mental unsoundness for which asylum treatment is considered necessary, and to the marked decline in the rate of discharge (including deaths) from asylums.
From Nature 18 July 1907.