By Will Stone Psilocybin mushrooms ready for harvest in a humidified chamber. Researchers have shown that a dose of psilocybin can help people quit smoking. John Moore/Getty Images hide caption The long-running campaign against smoking could find reinforcements from the new wave of research into psychedelics. Though much of the attention around psychedelics has focused on depression and other mental health conditions, researchers believe these substances also hold the potential to transform addiction treatment. A new study makes the strongest case yet for a psychedelic drug's impact on smoking, which remains the leading cause of preventable death in the U.S. The trial, conducted by a team at Johns Hopkins University, compared nicotine patches to the active ingredient in magic mushrooms, known as psilocybin.…