Within the United States, Marijuana has become approved for PTSD treatments. Many veterans suffering from PTSD can find relief in the form of cannabis. Properties of cannabis regulate the system that produces fear, anxiety, and nightmares. In 2009, researchers tested patients with a synthetic cannabinoid and found nightmare intensity, daytime flashbacks, and nightsweats to be significantly reduced. Cannabis has also been found to improve sleep duration and sleep quality for those suffering from PTSD.