The anxiety-relief effects of marijuana are well known but scientists have found for the first time how the controlled use of the drug may help people in distress. Sachin Patel a professor of psychiatry and molecular physiology at Tennessee-based Vanderbilt University identified cannabinoid receptors in the brain through which marijuana exerts its effects. The cannabinoid receptors are located in a key emotional hub in the brain involved in regulating anxiety and the flight-or-fight response. 'The discovery may help explain why marijuana users say they take the drug mainly to reduce anxiety' Patel said. Led by first author Teniel Ramikie a