Sometimes these side-effects can be removed by simply reducing the patient's antipsychotic drug dosage. Unfortunately, such reduction in drug dosage often causes patients to relapse back into psychosis. Sometimes the eyes go into spasm and roll back into the head. Such reactions usually take place within the first 24 to 48 hours after therapy has begun or, in a small number of cases, when dosage is increased. Males are more vulnerable to the reactions than females, and the young more so than the elderly.
High doses are more likely to produce such effects.
Although these reactions respond dramatically to the intramuscular injection of antihistamines or anti-parkinson agents, they are frightening and are best avoided by starting with lower antipsychotic drug dosages. Akinesia, a key feature of parkinsonism, may be overlooked, but if the patient is asked to walk briskly for some 20 paces, diminution of the swing of the arms can be noted, as can loss of facial expression. It is now known that many cases of tardive dyskinesia are reversible and that many cases do not progress. Early signs of tardive dyskinesia are mostly seen in the area of the face. Movements of the tongue inside the buccal cavity that consist of retraction of the tongue on its longitudinal axis or irregular rotation around the longitudinal axis, with frequent movements in lateral directions, are thought to be the earliest signs.