MDMA produces dose-dependent increases in reward responsivity, a measure of anhedonia, in rats, along with dose-dependent deficits in attention and short-term memory, and increases in prosocial interaction in male but not female rats. The desirable prohedonic effects and undesirable cognitive disruptions do not persist beyond 24 hours. These results characterize MDMA as a promising prohedonic treatment despite short-lived cognitive impairment following acute administration.
Adolescent monkeys exposed daily to the cannabis compound Δ9-THC for six months, then tested about a year later as adults on a touchscreen attention task, required higher acute doses of Δ9-THC to impair their performance compared with animals that had not been exposed during adolescence. The impairment itself was dose-related and occurred whether the drug was given by injection or orally, though potency and timing differed. These results suggest that heavy cannabis use during adolescence can produce a lasting tolerance that persists into adulthood, even after a long period of abstinence.