By By Marcus Hondro May 20, 2015 in Science Scientists in Pakistan who conducted a study on marijuana say the drug stunts the growth of boys who use it. Alarmingly, they say their study found that heavy users of the drug at a young age grew on average four inches shorter than non-smokers. Study: Pot stunts growth The scientists, from Pir Mehr Ali Shah Agriculture University in Rawalpindi, Their research The researchers followed their study-participants until young adulthood and said by age 20 there was a remarkable difference between the groups: on average the marijuana smokers were 4.6 inches shorter and 9 pounds lighter than the boys who did not smoke pot. "Marijuana use may provoke a stress response that stimulates the onset of puberty but suppresses growth rate,” study leader Dr. Syed Raza Rizvi said. The researchers also found stress levels higher in marijuana-smoking youth, that despite a common belief the reverse is true. Dr. Rizvi said their findings will have a dramatic impact on the study of marijuana and puberty. Marijuana and teen brains While marijuana is becoming popular as a medicine, there are studies showing that it has negative effects, in particular for teenagers. Some studies have found that marijuana shrinks and rewires ; however, many There have also been numerous studies to link marijuana usage and "Some recent studies suggest that regular use in teenage years leads to a permanent decrease in IQ. Other research hints at a possible heightened risk of developing psychosis," Dr. Gupta has said. "If they are adamant about trying marijuana, I will urge them (his children) to wait until they're in their mid-20s when their brains are fully developed." The scientists, from Pir Mehr Ali Shah Agriculture University in Rawalpindi, presented their findings at the European Congress of Endocrinology in Dublin this week. They examined growth hormone levels in the blood of 217 boys they classified as "cannabis-addicted" and another 220 boys who did not smoke marijuana.Their research found the level of some hormones prevalent in puberty were increased in the group who smoked marijuana, hormones such as luteinising hormone (LH) and testosterone. However, the researchers also said growth related hormones, important in a developing boy's body, were decreased in those who smoked marijuana.The researchers followed their study-participants until young adulthood and said by age 20 there was a remarkable difference between the groups: on average the marijuana smokers were 4.6 inches shorter and 9 pounds lighter than the boys who did not smoke pot."Marijuana use may provoke a stress response that stimulates the onset of puberty but suppresses growth rate,” study leader Dr. Syed Raza Rizvi said. The researchers also found stress levels higher in marijuana-smoking youth, that despite a common belief the reverse is true. Dr. Rizvi said their findings will have a dramatic impact on the study of marijuana and puberty.While marijuana is becoming popular as a medicine, there are studies showing that it has negative effects, in particular for teenagers. Some studies have found that marijuana shrinks and rewires young brains , other findings suggest it is a gateway drug that can lead to use of other, more harmful drugshowever, many studies have found that is not so.There have also been numerous studies to link marijuana usage and psychosis in teenagers. Medical doctor and broadcaster Dr. Sanjay Gupta has spoken in favour of medical marijuana, but not in favor of marijuana overall and is particularly concerned about young people smoking pot."Some recent studies suggest that regular use in teenage years leads to a permanent decrease in IQ. Other research hints at a possible heightened risk of developing psychosis," Dr. Gupta has said. "If they are adamant about trying marijuana, I will urge them (his children) to wait until they're in their mid-20s when their brains are fully developed." More about boys and marijuana, marijuana stunts growth, smoking pot boys and marijuana marijuana stunts gro... smoking pot