In three patients tics were quantitatively analyzed in a psychophysiological study employing serial polygraphic analysis. Two classes of tic were described both electrophysiologically and clinically. The simple tic was thought to reflect a basic neurophysiological disorder. The complex tic, (possibly a derivative of the simple variety) carried psychological significance. A doubleblind placebo controlled drug study using haloperidol indicated that while the administration of the drug was associated with a significant reduction of total tics, the drug was associated with either positive or negative placebo influences on the frequency of complex tics. A variety of psychological factors involved in these differing placebo effects were considered responsible for both beneficial and ineffectual drug influences. Both intrapsychic and territorial restraint were suggested as specifically significant in the genesis of the complex tic.