In this study, both an older neuroleptic (Haldol or “haloperidol”) and a newer atypical neuroleptic (Zyprexa or “olanzapine”) caused significant shrinkage in the higher level parts of the brains in monkeys. Source: Neuropsychopharmacology 9 March 2005
Haldol, Olanzapine Cause Brain Shrinkage in Monkeys
Three groups of six macaque monkeys each were exposed to oral haloperidol, olanzapine or sham for a 17-27 month period.
There was an 8-11% reduction in mean fresh brain weights as well as left cerebrum fresh weights and volumes in both drug-treated groups compared to sham.
The differences were observed across all major brain regions (frontal, parietal, temporal, occipital, and cerebellum), but was increased in the frontal and parietal regions in both gray and white matter.
There was a similar shrinkage in volume that was greater in drug-treated monkeys compared to sham.
(Note: As originally reported here, the study looked at changes in volume caused by “tissue fixation” itself, but this secondary focus is not relevant to this concern about drug-induced brain changes.)
Medical study source:
The Influence of Chronic Exposure to Antipsychotic Medications on Brain Size before and after Tissue Fixation: A Comparison of Haloperidol and Olanzapine in Macaque Monkeys.
by Dorph-Petersen KA, Pierri JN, et al. from University of Pittsburgh.
Source: Neuropsychopharmacology 9 March 2005
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