Reversal of head drop after discontinuation of olanzapine in a DLB patient.

We present a 72-year-oldpatient with probable diffuse Lewy body disease and visual hallucinations, who developed subacute reversible "dropped head syndrome" and parkinsonian signs after the introduction of olanzapine at a total daily dose of 10 mg. One week after olanzapine was withdrawn, the patient's posture started to improve. Further improvement was achieved after dopaminergic substitution. Clinical and electrophysiological observations might indicate neck extensor myopathy due to axial rigidity or focal neck dystonia, induced by dopamine receptor blockade.