Mescaline produces pathological aggression in rats regardless of age or strain

Several measures of aggressive behavior were investigated in three ages (40–50, 90–110, and 180–200 days old) and in three strains (Sprague-Dawley, Wistar, and Long-Evans) of rats before and following the administration of mescaline hydrochloride in a shock-elicited aggression situation. The measures included the number of fights, duration of fighting, latency of fighting, number of bites inflicted, and a composite index of pathological aggression. During predrug baseline testing it was found that older rats, regardless of strain, engaged in more frequent fights that were longer in duration and more intense than younger animals. When the animals were tested with mescaline, they engaged in significantly more fights, biting, and pathological aggression than during baseline testing regardless of their age or strain. These results suggest that mescaline-induced pathological aggression in rats is a robust phenomenon.