Introduction

Movement disorders developing in the early phase of exposure to antidopaminergic medication or following dose increments are overwhelmingly dystonic in type. However, it must be borne in mind that acute dystonias are not the only motor disorders that can occur at these times. There may be myoclonic jerks of face, neck and limbs as well as jerky tongue protrusions, lip smacking, blinking, tic-like shoulder shrugging and even writhing, choreoathetoid-type arm and leg movements. Such disorders have been referred to as initial dyskinesias (Gerlach, 1979). They are certainly a relatively uncommon reaction to antidopaminergic introduction or increment, although how uncommon is unclear. Similarly, although transient, their relationship to other extrapyramidal syndromes is unknown. Over a few days, some of these disorders may blend into the features of akathisia.

From our point of view, however, the vast majority of the early and incremental disorders that we shall have to deal with will be of dystonic type, and it is to this area that we shall devote our attention.

The concept of dystonia

Before embarking on a discussion of acute dystonia, it might be of value to review the basic concept of dystonia itself.

The term ‘dystonia’ is one that has caused a certain grief to both psychiatry and neurology (Owens, 1990). Its generic meaning obviously refers to a primary abnormality of voluntary muscle tone. This was the sense in which Kinnier Wilson used it, i.e. ‘any variability of muscle tone’.