The effect of complete social deprivation in early postnatal ontogenesis on adult behavior in Wag/Rij rats with a genetic predisposition to the development of absence epilepsy was studied. From the 2 nd to the 8 th day of life, a 3-hour daily isolation of the pups from the mother and siblings was performed, the control animals were handled. In adulthood, offspring behavior was tested in an elevated plus-maze, an open field, and for an ability to learn the conditioned reflex of active avoidance. In isolated earlier rats, an increase in emotional reactivity, exploratory behavior in a potentially dangerous space, the speed of learning a conditioned reflex with negative painful reinforcement, and a disturbance of the formation of a defensive reaction were revealed. It is assumed that high emotional reactivity creates the prerequisites for the development of absence epilepsy.