Introduction

When the concept of tardive dyskinesia was first mooted, appraisals of the supportive evidence ranged from ‘thoroughly convincing’ (Marsden, Tarsy and Baldessarini, 1975), through ‘compelling’ (Kane and Smith, 1982), to die-hard scepticism (Crow et al., 1983). How could such diversity of opinion have been sustained?

It has already been seen that antipsychotic drugs are neither necessary nor sufficient to ‘cause’ involuntary movement disorders. Individuals never exposed to these drugs can develop identical disorder, but not everyone comparably exposed does so. The divergence in appraising the initial evidence arose from a conflict between the wish to understand the disorder as opposed to merely establishing its validity. Those who wished to understand were strongly influenced by the lingering recollection of a literature suggesting that schizophrenia may be a condition that can itself be associated with the development of involuntary movements.

The descriptive evidence

The early descriptive writers on schizophrenia clearly recognized that all was not well in their patients' motor domains. Kraepelin and Bleuler both acknowledged the importance of motor signs and both went along with the inclusion of Kahlbaum's ‘Katatonie’ as one subtype. Beyond this however – in the realm of movement disorders of hyperkinetic type – they parted company fiercely.

Bleuler (1911; pp. 185 and 191) described patients: ‘performing all kinds of manipulations with their teeth … (with) grimaces of all kinds, (and) extraordinary movements of the tongue and lips.’