Haloperidol withdrawal and weight changes in autistic children.

The long-term effects of haloperidol on weight were assessed in 30 children, 25 males and 5 females, diagnosed with autistic disorder whose ages ranged from 3.08 to 8.42 years. They received haloperidol (0.25-3.50 mg/day; mean 1.26 +/- 0.84) for 6 months followed by a 4-week drug withdrawal period. Weights obtained on the last day of the 6-month haloperidol period were compared to weights obtained following drug withdrawal. There was no significant difference between the mean weights obtained on the last day of haloperidol administration (24.799 +/- 9.741 kg) compared to the mean weights at the end of the fourth week of the placebo period (24.644 +/- 9.833 kg). Weights increased during the first week of drug discontinuation (24.879 +/- 9.855 kg), but decreased during each following week of drug withdrawal. Weight was measured monthly during the 6-month haloperidol treatment period for 8 of the 30 subjects. In this subsample, weight gain was greater during the 1-month period lasting from the end of the 4-week drug withdrawal to the end of the first month after resuming haloperidol treatment than weight gain prior to drug withdrawal, between the fifth and sixth month of haloperidol treatment.