A study released this week from the Journal of the American Medical Association Psychiatry suggests that the harms associated with long-term marijuana use are much less than previously claimed. Time reports: Even after years of heavy use, marijuana doesn’t seem to have much of an impact on the physical health of the body. So finds a recent study published in JAMA Psychiatry, which analyzed data from a group of 1,037 New Zealanders followed from their birth until age 38. The researchers, led by Madeline…