The natural history of tardive dyskinesia.

Follow-up data from the first 100 patients with early dyskinesia are presented. After an average of 40.9 months, the cohort showed statistically significant decreases in tardive dyskinesia (TD) ratings. After TD onset, ratings decreased for 4 years, then plateaued and rose during the 7th year. Age was not a negative prognostic factor in this cohort. Improvement in TD correlated significantly with fewer neuroleptic-free periods before and more neuroleptic-free periods after TD onset. Neuroleptic dosage correlated negatively with improvement in trunk and dystonia ratings. Improvement in TD is the usual finding in longitudinal studies of TD cohorts. Follow-up studies of neuroleptic-treated groups with varying proportions of patients showing TD, by contrast, tend to show increased TD because new TD cases more than offset improvement. A naturalistic study with pharmacotherapy tailored to the underlying psychiatric disorder and conducted long-term from TD onset is the ideal design for investigating the natural history of TD.