Sir.—Dr Schmitt's article repeats a number of misunderstandings and does not reflect current knowledge in the field.
Dr Schmitt equates minimal brain dysfunction (MBD) with minimal brain damage. The word "dysfunction" is used by most to explicitly exclude any connection with neurological damage. Current evidence strongly supports the view that a large fraction of MBD is of genetic origin and is not the product of structural abnormalities within the central nervous system. This being so, the presence or absence of the neurological history, soft neurological signs, or electroencephalographic abnormalities is entirely irrelevant. This absence of objective signs may make the physician's life more difficult, but the absence of such signs is the rule, not the exception, in all major psychiatric illnesses.
2. Dr Schmitt seems unhappy that the prevalence for MBD has been claimed to be of the order of magnitude of 5% to 10%. This is a