Thioridazine dose effects with reference to stereotypic behavior in mentally retarded residents.

Eleven residents receiving long-term thioridazine treatment were studied while receiving their previous dose, standardized low and high doses (1.25 and 2.50 mg/kg per day), and placebo conditions. For theoretical reasons, subjects were also classified by degree of stereotypic behavior on the Fairview Problem Behavior Checklist (Barron & Sandman, 1983). Ratings of hyperactivity and self-injury were significantly lower during the higher as compared with the lower dose condition. Subjects classified as in the high-stereotypy group had significantly and substantially higher levels of maladaptive behavior on several other clinical variables. When all four drug conditions were compared, no significant drug effects were detected. However, high-stereotypy subjects responded significantly better to the drug than low-stereotypy subjects on ratings of Lethargy/Social Withdrawal and Hyperactivity on the Aberrant Behavior Checklist (Aman, Singh, Stewart, & Field, 1985a). The findings were related to previous dosage research and the literature on stereotypic behavior.