Researchers tested whether psilocybin, a compound found in magic mushrooms, could be addictive by examining reward-seeking behavior in rats. The study found that psilocybin did not create rewarding effects that would typically lead to addiction, and only temporarily changed specific behaviors like head-twitching and grooming while the drug was active. These findings suggest that psilocybin has a low addiction potential and may be safe for therapeutic use in treating mental health conditions.