Regular Marijuana Use Weakens Stress Response

Researchers at Washington State University have studied the effects of regular marijuana use and found that cannabis weakens the body’s physiological response to stress.

The Effect of Marijuana Depends on Dosage and Gender

The scientists conducted experiments on rats, separating males and females into different cages. Vaporizers filled with cannabis extract were installed in the cages. The extract contained 69.81% THC, 0.89% tetrahydrocannabivarin, 0.83% cannabichromene, 2.69% cannabigerol, and 1.51% cannabinol. The system allowed the rodents to self-administer cannabis at any time. To do so, the rats had to poke their noses twice into a special hole, after which vapor with THC was released into the cage in varying doses: 75 mg, 150 mg, or 300 mg per ml.

The experiments lasted for 30 days. Afterward, the researchers analyzed the data and found the following:

• Female rats consumed cannabinoids much more frequently than males. For example, males inhaled vapor with 75 mg THC per ml up to 17 times a day, while females did so up to 28 times.
• The frequency of extract use depended on the THC concentration—the higher the dose, the less often the rats used the vaporizer.
• After a stressful situation (the animals were stretched using a special device), male rats showed increased levels of the “stress hormone” corticosterone, while females did not. In other words, female rats did not become aroused by danger.

Cannabis Affects Men and Women Differently

Dr. Carrie Kettler from the Department of Neuroscience commented on the results: “Disruption of the hormonal response to stressful situations can lead to serious consequences and harm a person. The field of marijuana research is expanding due to the legalization of the plant, and our experiments will help determine the positive and negative effects of marijuana use in women and men.”

Project co-author Ryan McLaughlin stated that the anti-stress effect of cannabis directly depended on the dosage and the sex of the rats. The strongest effect was observed in females given the highest THC dose (300 mg per ml). The reason why males continued to respond to stress despite cannabis use will be the subject of future research. According to the scientists, corticosterone helps rodents adapt to their environment. If THC blocks the secretion of the human hormone cortisol, then marijuana use may pose greater risks for women than for men.