Rimonabant is an anti-obesity drug that works by blocking the cannabinoid receptor type 1 (CB1). It was the first selective CB1 receptor blocker and was effective in reducing appetite and aiding in smoking cessation. However, it was suspended in 2009 due to psychiatric side effects including depression, anxiety, and suicidal tendencies that were linked to its mechanism of blocking CB1 receptors in the brain. CB1 receptors are involved in modulating emotion and stress responses.