Choreic movements induced by the use of methadone

A 25-year-old man received methadone hydrochloride maintenance therapy for heroin addiction. Choreic movements involving the upper limbs, torso, and speech mechanisms developed. Discontinuation of methadone resulted in complete alleviation of the abnormal movements with no recurrence during the subsequent eight months. To our knowledge, this is the first recorded instance of a movement disorder induced by an opiate. The mechanisms by which drugs may after neurotransmitter relationships in the brain and produce symptoms of this type are discussed.