Background. Apart from ageing, the factors associated with vulnerabili
ty to the emergence of tardive dyskinesia are poorly defined. Method.
Risk factors associated with the presence of a chronic choreic or dyst
onic disorder were assessed in a cross-sectional comparison of anamnes
tic and clinical data in a homogeneous group of 64 young psychotic pat
ients (under 40 years of age) on chronic low to moderate doses of neur
oleptics. Results. Dyskinetic subjects presented more indirect indicat
ors of occult brain damage, such as a perinatal event or traumatic bra
in injuries in infancy and early childhood; neurological examination s
howed more anomalies in dyskinetic patients than in non-dyskinetics, w
ith a higher prevalence of facial release reflexes. Conclusion. These
data may support the hypothesis that occult acquired brain damage is i
mportant in the genesis of this 'drug-induced' disorder.