AbstractThe ontogeny of the behavioral effects of lysergic acid diethylamide (LSD) was examined in cats between the ages of 4 and 112 days postpartum. The kittens showed little LSD‐induced behavioral change prior to 14 days of age. By the age of 21 days, however, the kittens exhibited many of the behavioral signs characteristic of LSD‐induced behaviors in adult cats. These behaviors include...