Tardive dyskinesia: fluctuating patient or fluctuating rater.

Tardive dyskinesia (TD) is usually described as fluctuating in its clinical manifestations. We attempted to quantify fluctuations in TD using the Abnormal Involuntary Movement Scale (AIMS). Three psychiatrists rated multiple video-recorded examinations of four outpatients with mild TD. The unexpected finding was that within-rater variability dominated within-patient variability.