The latest finding by
University of Pittsburgh researchers shows that heavy marijuana use activates alterations in a molecular brain pathway that may contribute to the cognitive symptoms of schizophrenia.
While the use of cannabis sativa is not the cause of schizophrenia, the study shows that conditions for individuals predisposed to the illness are often made worse by heavy pot use, points out Dr. David Lewis, an author of the study and professor of psychiatry at the University of Pittsburgh.
“Heavy use, particularly in adolescence, appears to be associated with an increased risk for the later development of schizophrenia, and the course of illness is worse for people with schizophrenia who use marijuana,” says Lewis. “If we understand how marijuana affects the brain to worsen symptoms, it will tell us biologically how to intervene (through medication) to improve the symptoms.”
The study, funded in part by the
National Institute of Health, comes at a time when researchers are revisiting the controversial and damaging effects of marijuana on the brain due to the more potent pot circulating today. While medicinal uses of marijuana have been cited—for glaucoma or pain relief—the dangers of the drug on the brain outweigh the benefits, many researchers say.
“It's like any other drug that acts on the brain," says Dr. Lewis. "Just because there are potential benefits for individuals with certain illnesses doesn't mean if you're an adolescent you can use it without potential adverse effects."
The study found that the expression of the cannabinoid 1 receptor (CB1R), one of the main chemical ingredients of marijuana, is significantly reduced in the brains of individuals with schizophrenia. Activation of CB1R impairs signaling of an important neurotransmitter that is essential for core cognitive processes such as working memory.
The findings were published this month in the
Archives of General Psychiatry, one of the JAMA/Archives journals.
Writer: Debra Smit
Source: Dr. David Lewis, Michele Baum, University of Pittsburgh