Rhesus monkeys (Macaca mulatta) were housed in individual cages and could hear, see, and touch other monkeys in adjacent cages. Monkeys received food and water ad libitum. Monkeys were randomly assigned to one of four treatment groups: drug-naïve control (CTRL, n = 10; 6.0 ± 0.5 years), low dose haloperidol (LHAL, n = 10; 0.7 mg/kg b.i.d., p.o.; 6.0 ± 0.4 years), high dose haloperidol (HHAL, n = 8; 2.0 mg/kg b.i.d., p.o.; 6.2 ± 0.4 years), and clozapine (CLZ, n = 10; 2.6 mg/kg b.i.d., p.o.; 6.2 ± 0.4 years) using previously established protocols (79 (link)–82 (link)). Males and females were equally represented in each group. Antipsychotics were mixed with powdered sugar and given in peanut butter or fruit treats and administered for 6 months. Monkeys in the CTRL group received powdered sugar in peanut butter or fruit treats. Monkeys received social enrichment, human interaction, variety in diet, and age-appropriate objects. Subjects were observed a minimum of twice daily for the duration of the experiments. No overt physical signs of dystonia (abnormal posturing or repetitive movements in the back, neck, jaw, eyes, face, or tongue), drug induced parkinsonism (tremor, rigidity, poverty of movement) or tardive dyskinesias (involuntary choreoathetoid movements) were observed. The care of the animals and euthanasia procedures in this study were performed according to the National Institutes for Health Guide for the Care and Use of Laboratory Animals and were approved by the Institutional Animal Care and Use Committees at Emory University and Wake Forest University.
Free full text: Click here
