The long-running debate over the dangers of cannabis will be reignited by a study that challenges the idea that experimenting with the drug is harmless and does not lead to further drug use.
Prof Yasmin Hurd, Dr Sabrina Spano and Dr Maria Ellgren, working at the Karolinksa Institute, in Sweden, have demonstrated that cannabis can enhance future sensitivity to heroin.
Studying events in the brain of adolescent rats after cannabis exposure, they found that the drug affects the brain's natural chemicals, called endogenous opioids. The chemicals are known to play a role in heightening positive emotions and creating a sense of reward....