Brain Damage Data from Marijuana Use / Anti-Marijuana Educationa

Data Show Anatomical Brain Abnormalities from Marijuana Use. Credits at end of video. Regional Brain Abnormalities Associated With Long-term Heavy Cannabis Use. Murat Yücel, PhD, MAPS; Nadia Solowij, PhD; Colleen Respondek, BSc; Sarah Whittle, PhD; Alex Fornito, PhD; Christos Pantelis, MD, MRCPsych, FRANZCP; Dan I. Lubman, MB ChB, PhD, FRANZCP; General Psychiatry. 2008;65(6):694-701. In the human brain, the hippocampus is associated with the regulation of emotion and memory, while the amygdala controls fear and aggression. Recently a study was conducted by Dr. Murat Yücel and associates from the ORYGEN Research Centre and the Neuropsychiatry Centre at the University of Melbourne in order to determine whether long-term heavy cannabis use is associated with gross anatomical abnormalities in two cannabinoid receptor--rich regions of the brain, the hippocampus and the amygdala. In the study, Yucel's team did high-resolution MRIs on 15 men who smoked more than five joints a day for more than 10 years with no history of poly-drug abuse. They compared those with scans of 16 men who did not use marijuana. In addition, all the men took verbal memory tests and were examined for symptoms of psychiatric disorders. Results indicated that the hippocampus of marijuana users was 12 percent smaller, and that the amygdala of marijuana users was 7.1 percent smaller than among nonusers. Cannabis use also was associated with sub-threshold symptoms of psychotic disorders. Lead researcher Murat Yücel said, "This study shows long-term, heavy cannabis use causes significant brain injury, memory loss, difficulties learning new information, and psychotic symptoms, such as delusions of persecution, paranoia, delusions of mind-reading, and bizarre social behaviors in even non-vulnerable users." "The more marijuana was used, the more these individuals were likely to show reduced brain volumes in the hippocampus and amygdala, as well as being more likely to develop symptoms of psychotic disorders and to have significant memory impairment." "There is ongoing controversy concerning the long-term effects of cannabis on the brain," the authors write. "These findings challenge the widespread perception of cannabis as having limited or no neuroanatomical sequelae. Although modest use may not lead to significant neurotoxic effects, these results suggest that heavy daily use might indeed be toxic to human brain tissue. Further prospective, longitudinal research is required to determine the degree and mechanisms of long-term cannabis-related harm and the time course of neuronal recovery after abstinence." Author Affiliations: ORYGEN Research Centre (Drs Yücel, Whittle, and Lubman) and Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health (Drs Yücel, Whittle, Fornito, and Pantelis), Melbourne, Australia; School of Psychology and Illawarra Institute for Mental Health, University of Wollongong, Wollongong, Australia (Dr Solowij and Ms Respondek); and Schizophrenia Research Institute, Sydney, Australia (Dr Solowij). All text and images from Fair Use.