ABSTRACT
As explained earlier, subnormality was a term introduced by the Mental Health Act 1959 and it is, therefore, a legal and not a scientific concept. However, underlying both subnormality and severe subnormality is the condition of amentia—literally, lack of mind. The causes of amentia fall into two broad divisions, the pathological and the subcultural. The pathological causes are in general responsible for the more severe degrees of amentia, in which there are demonstrable abnormalities of development or functioning of the brain.
