Frequent Δ- tetrahydrocannabinol exposure during adolescence impairs sociability in adult mice exposed to an aversive painful stimulus.

Early-life exposure to Δ-tetrahydrocannabinol (Δ-THC), the intoxicating constituent of cannabis, may produce enduring neurochemical changes in brain structures involved in the regulation of sociality but it is still unclear how such changes influence social behavior later in life. In the present study, we exposed male mice to moderate daily doses of Δ-THC (5 mg/kg, intraperitoneal) during adolescence (postnatal day, PND, 30 to 43) and, when animals reached adulthood (PND70), we assessed their performance in the three-chamber social interaction task before and 3 weeks after injection of the chemical irritant formalin (1 % vol, intraplantar), which produces both immediate and persistent pain-related behaviors in mice. Prior Δ-THC treatment did not alter social interaction in control adult mice but disrupted it in animals that developed lasting sensory abnormalities following formalin injection.