There's no evidence suggesting permanent brain damage to adults who use cannabis.
February 7, 2011
Cannabis May Influence Onset of Psychosis
Research to be published this summer finds that the use of cannabis is associated with the early onset of psychosis. Christie Nicholson reports.
This particular study found that marijuana use is associated with early development of psychosis. Scientists analyzed 83 studies involving over 8,000 subjects who used pot and over 14,000 subjects who did not. They compared the age of onset for psychosis between these groups. And they found that those who used cannabis developed psychosis nearly three years younger than those who did not use any pot.
http://www.scientificamerican.com/podcast/episode/cannabis-may-influence-onset-of-psy-11-02-07/Don't Rule Out Marijuana as Trigger for Schizophrenia
By: RICHARD HYER, Clinical Psychiatry News Digital Network
09/21/11
CHICAGO – The idea that cannabis use might trigger a patient’s first psychotic episode is one that needs to be taken seriously, Dr. John Csernansky said at a seminar on "Reinventing Inpatient Psychiatry."
"Are there patients out there who have schizophrenia who would not have had it without substance abuse? There may be," said Dr. Csernansky, chairman of the department of psychiatry and behavioral sciences at Northwestern University, Chicago. "This is a very hot topic and one that is genuinely frightening."
Cannabis use is frequent within 1-2 years before the first psychotic break. A variety of epidemiological studies suggest that cannabis use in adolescence (15-18) increases the risk for development of schizophrenia, even years later.
The connection between cannabis use and early psychosis is particularly concerning because substance abuse is common in schizophrenia. Cannabis, in particular, has a severe effect on the thalamus of the person with schizophrenia. This effect is worse than the effect of alcohol.
"It looks as though alcohol makes schizophrenia worse, whereas cannabis damages a part of the brain that maybe otherwise would have not been [damaged]," Dr. Csernansky said.
http://www.clinicalpsychiatrynews.com/single-view/don-t-rule-out-marijuana-as-trigger-for-schizophrenia/df0b545c0b.htmlGrowing Evidence Of Marijuana Smoke's Potential Dangers
ScienceDaily (Aug. 5, 2009) — In a finding that challenges the increasingly popular belief that smoking marijuana is less harmful to health than smoking tobacco, researchers in Canada are reporting that smoking marijuana, like smoking tobacco, has toxic effects on cells.
Scientists know that marijuana smoke has adverse effects on the lungs. However, there is little knowledge about marijuana's potential to cause lung cancer due to the difficulty in identifying and studying people who have smoked only marijuana.
The new study begins to address that question by comparing marijuana smoke vs. tobacco smoke in terms of toxicity to cells and to DNA. Scientists exposed cultured animal cells and bacteria to condensed smoke samples from both marijuana and tobacco. There were distinct differences in the degree and type of toxicity elicited by marijuana and cigarette smoke.
http://www.sciencedaily.com/releases/2009/08/090805110741.htmThe evidence is mounting.
