In a rodent model of fear conditioning, acute exposure to THC-dominant cannabis vapor before fear learning did not affect initial fear acquisition but impaired fear recall in females 24 hours later and prevented spontaneous recovery of conditioned fear in both sexes after two weeks. Acute cannabis before extinction training impaired extinction in females while enhancing it in males. Chronic THC exposure before conditioning initially potentiated fear responses, mainly in females, but did not affect spontaneous recovery. Cannabis exposure has complex effects on fear memory, though acute exposure before fear learning may destabilize fear memory long term, with potential implications for PTSD.
Cannabis vapor inhalation acutely increases food intake in both humans and rats, an effect driven by central cannabinoid 1 receptors. In humans, energy intake rose within the first 30 minutes of snack access, regardless of dose or gender, without altering the proportion of macronutrients consumed. In rats, cannabis vapor reduced the time to start eating and increased the number of feeding bouts, overriding homeostatic appetite regulation by boosting motivation to eat and reducing food reward devaluation. These feeding effects were not accompanied by changes in circulating appetite-associated hormones, and they depended on central, not peripheral, CB1 receptors.