Assesssing the prevalance and exploring the aetiology of intellectual disability in the early twentieth century: the experience of policy and practice in New South Wales

Abstract

From the beginning of the twentieth century to the failure of the passage of the New South Wales Mental Defectives Bill in 1930, several investigations were conducted in an attempt to assess the prevalence of intellectual disability in the Australian community. During this period, 7252 people were admitted to state mental hospitals in New South Wales with a diagnosis of congenital or infantile mental deficiency, including the diagnostic subcategories of epileptic insanity and general paralysis of the insane. Using primary source material including annual reports of the New South Wales Lunacy Department, New South Wales Inspector General of the Insane Correspondence Files, and aggregated diagnostic data from patient case notes, this article will discuss attempts to assess the prevalence of intellectual disability in Australia and more specifically in New South Wales during the period and attempts to attribute causation. Epilepsy and syphilis will be discussed in terms of causation and correlation as specific co-morbid conditions associated with intellectual disability.