Acute dystonic reaction in an elderly patient with mood disorder after titration of paroxetine: possible mechanisms and implications for clinical care.

The administration of a serotonin reuptake inhibitor may lead to extra pyramidal signs, as reported in the literature. The risk seems to be increased in elderly people. We describe a case of acute dystonic reaction to paroxetine treatment in an elderly patient, who presented with a bipolar affective disorder. The underlying mechanism, possibly generated in the subcortical motor areas, is linked to changes that occur in the pharmacokinetic variables, the decreased neuroplasticity of ageing neurones and to previous exposure to neuroleptic medications.