Many states have legalized marijuana to treat conditions ranging from anxiety to glaucoma. However, it's important to recognize that chemically, there is no distinction between recreational and medical marijuana, says Aaron Weiner, PhD, a licensed clinical psychologist and addictions specialist. "In states that have both recreational and medicinal programs, the difference between the two generally only extends to the amount that can be purchased at one time, and how high the taxes are on the product," he says. "The cart is very much before the horse right now in terms of the medical marijuana industry." Overall, THC is a safer compound than many other drugs like nicotine or opiates, Piomelli says.