Neuroleptic-induced Parkinson's syndrome: clinical features and results of treatment with levodopa.
Twenty six consecutive patients with neuroleptic-induced Parkinson's syndrome (NIPS) are described. Their median age was 61 years, 60% were female, and most had received chronic neuroleptic medication for psychiatric indications. The clinical features were indistinguishable from idiopathic Parkinson's disease, except for the presence of co-existing orofacial chorea, limb dyskinesia or akathisia which provided an aetiological clue in 11 cases. Complete resolution of NIPS occurred in only two patients, one of whom later developed Parkinson's disease. Sixteen patients were treated with 300-1000 mg levodopa/benserazide for up to 4 years with few adverse effects but therapeutic response was disappointing.