Experience and perspectives on the classification of organic mental disorders.

The official diagnostic classification systems have been increasingly employed in the last few years, and this is true of both ICD-10 and DSM-IV. We will propose a few principles which should be considered when revisions are attempted. Our existing classifications should be simplified, but new syndromes incorporated where they have pathological justification. Links to other specialist diagnostic classifications should be made (e.g. in epilepsy, sleep disorders, dementias) wherever possible. A broader range of 'Neuropsychiatric Disorders' should be incorporated, including alcohol-related organic disorders, head injury, sleep disorders, if possible including the 'psychogenic syndromes'. Progressive, degenerative disorders need to be clearly distinguished from non-progressive syndromes, and some gradation of severity needs to be built into the classificatory system. Finally, the definitions need to be concise and accurate.