I thought I'd offer multiple links.
Note: I'm not trying to say that marijuana should be illegal or legal, and am definitely not negating its medicinal qualities. I know most are not very current (though they're all within the last ten years, so are probably scientifically rigorous) but I'd like to provoke a serious discussion. Any anecdotes? I believe I am one such case where cannabis use pushed me over the edge.
Included are the first two sources (which are both 2012).
"Adolescence represents a critical period for brain development and the endocannabinoid system plays a crucial role in the regulation of neuronal refinement during this period. Cannabis is the most consumed drug among adolescent people and its heavy use may affect maturational refinement by disrupting the regulatory role of the endocannabinoid system. In animals, adolescent cannabinoid exposure has been reported to cause long-term impairment in specific components of learning and memory and to differentially affect emotional reactivity with milder effects on anxiety behaviour and more pronounced effects on depression-like behaviour. Moreover, adolescent exposure to cannabinoids might represent a risk factor for developing psychotic-like symptoms at adulthood. Also epidemiological studies suggest that heavy adolescent cannabis use may increase the risk of cognitive abnormalities, psychotic illness, mood disorders and other illicit substance use later in life. In conclusion, the available data point to the hypothesis that heavy cannabis use in adolescence could increase the risk of developing psychiatric disorders, especially in people who already have a vulnerability to develop a psychiatric syndrome. Only few papers have investigated the neurobiological substrates of this vulnerability, thus further studies are needed to clarify the molecular mechanisms underlying the effect of cannabis on the adolescent brain."
"Researchers looking at the effects of cannabis on the brain have made some interesting discoveries. The effect is similar to some of the symptoms of schizophrenia, say Dr. Matthew Jones and colleagues at Bristol University, UK. They predicted that the detrimental impact of cannabis on memory and cognition might be caused by brain networks being “disorchestrated.”
Normally, specific parts of the brain are tuned into each another at certain frequencies, say the researchers. This rhythmic activity produces brain waves and allows information to be processed in order for us to react.
The team used the analogy of an orchestra to explain how this works. They say that brain activity can be compared to the performance of an orchestra in which string, brass, woodwind and percussion sections are joined together in rhythms dictated by the conductor. In a similar way, specific structures in the brain tune in to one another at certain frequencies. Their rhythmic activity creates brain waves, and the tuning of these brain waves normally allows information to be processed that guides our behavior. But cannabis causes disturbances in systems involved in concentration and memory, the team found.
The primary psychoactive ingredient of cannabis, known as THC, activates cannabinoid receptors, which are found in many brain areas. In the research, the team measured the electrical activity from hundreds of neurons in rats when given a drug similar to THC which also stimulates cannabinoid receptors.
This showed that the effects on individual brain regions were subtle, but brain waves across the hippocampus and prefrontal cortex were completely disrupted. These two brain areas are vital for memory and decision-making, so the rats were no longer able to accurately navigate a maze. Both areas are also involved in schizophrenia.
Findings are published in the Journal of Neuroscience. The authors write that these results show a possible mechanism behind the cognitive impairment caused by cannabis that was described by Dr Frederick T. Melges and his team back in 1970. Dr. Melges called the effect “temporal disintegration,” and described it as “difficulty in retaining, coordinating and serially indexing those memories, perceptions and expectations that are relevant to the goal one is pursuing.”
More recent studies suggest that THC given intravenously to healthy volunteers can induce several psychotic symptoms of schizophrenia, so the authors believe that THC studies be used to model broader aspects of the disease, not just cognitive dysfunction.
Dr. Jones commented, “Marijuana abuse is common among sufferers of schizophrenia and recent studies have shown that the psychoactive ingredient of marijuana can induce some symptoms of schizophrenia in healthy volunteers. These findings are therefore important for our understanding of psychiatric diseases, which may arise as a consequence of ‘disorchestrated brains’ and could be treated by re-tuning brain activity.”
Co-author Michal Kucewicz added, “These results are an important step forward in our understanding of how rhythmic activity in the brain underlies thought processes in health and disease.”
The researchers conclude, “These tools will continue to shed light on the neural mechanisms of working memory and decision making in health and disease.”
A 2012 review of current knowledge shows that the endocannabinoid system in the brain has a major role in schizophrenia. “Data reported so far clearly indicate the presence of a dysregulation in the endocannabinoid system in animal models of psychosis as well as in schizophrenic patients,” the review says.
Its authors, led by Professor Daniela Parolaro of the University of Insubria, Italy, add that animal models suggest that adolescence is “a highly vulnerable age for the consequences of cannabis exposure on different domains (such as cognition and social behavior) that are altered in psychotic disorders.”
They suggest that drugs which target the cannabinoid system are “a new therapeutic possibility for psychotic disorders.” However, they warn that drug studies so far have not had straightforward results, with different types of drug showing different effects.
But despite all these limitations, cannabidiol, a compound found in cannabis that activates cannabinoid receptors, has shown fairly consistent antipsychotic properties in animal tests. Recent studies indicate that cannabidiol may be as effective as antipsychotics in treating schizophrenia.
The benefit of cannabidiol appears similar to that gained from atypical antipsychotic drugs, and so far it is considered a safe and well-tolerated compound. Future studies will need to compare its antipsychotic effects against standard drugs for schizophrenic patients."
I'm actually really interested to try cannabidiol (perhaps mixed with a small amount of other cannabinoids) in the future by prescription for my disorder.
http://psychcentral.com/lib/2012/cannabis-may-cause-schizophrenia-like-brain-changes/
http://jop.sagepub.com/content/26/1/177.short
http://web.lemoyne.edu/~hevern/storiedconduct/files/Cannabis and psychosis.html
http://www.emaxhealth.com/1275/marijuana-use-leads-earlier-psychosis-bipolar-disorder
http://healthland.time.com/2011/02/...er-onset-of-schizophrenia-in-research-review/
http://articles.latimes.com/2007/jul/27/science/sci-marijuana27
http://www.ncbi.nlm.nih.gov/pubmed/15763748
http://www.sciencedaily.com/releases/2007/07/070731125526.htm
Thanks
Note: I'm not trying to say that marijuana should be illegal or legal, and am definitely not negating its medicinal qualities. I know most are not very current (though they're all within the last ten years, so are probably scientifically rigorous) but I'd like to provoke a serious discussion. Any anecdotes? I believe I am one such case where cannabis use pushed me over the edge.
Included are the first two sources (which are both 2012).
"Adolescence represents a critical period for brain development and the endocannabinoid system plays a crucial role in the regulation of neuronal refinement during this period. Cannabis is the most consumed drug among adolescent people and its heavy use may affect maturational refinement by disrupting the regulatory role of the endocannabinoid system. In animals, adolescent cannabinoid exposure has been reported to cause long-term impairment in specific components of learning and memory and to differentially affect emotional reactivity with milder effects on anxiety behaviour and more pronounced effects on depression-like behaviour. Moreover, adolescent exposure to cannabinoids might represent a risk factor for developing psychotic-like symptoms at adulthood. Also epidemiological studies suggest that heavy adolescent cannabis use may increase the risk of cognitive abnormalities, psychotic illness, mood disorders and other illicit substance use later in life. In conclusion, the available data point to the hypothesis that heavy cannabis use in adolescence could increase the risk of developing psychiatric disorders, especially in people who already have a vulnerability to develop a psychiatric syndrome. Only few papers have investigated the neurobiological substrates of this vulnerability, thus further studies are needed to clarify the molecular mechanisms underlying the effect of cannabis on the adolescent brain."
"Researchers looking at the effects of cannabis on the brain have made some interesting discoveries. The effect is similar to some of the symptoms of schizophrenia, say Dr. Matthew Jones and colleagues at Bristol University, UK. They predicted that the detrimental impact of cannabis on memory and cognition might be caused by brain networks being “disorchestrated.”
Normally, specific parts of the brain are tuned into each another at certain frequencies, say the researchers. This rhythmic activity produces brain waves and allows information to be processed in order for us to react.
The team used the analogy of an orchestra to explain how this works. They say that brain activity can be compared to the performance of an orchestra in which string, brass, woodwind and percussion sections are joined together in rhythms dictated by the conductor. In a similar way, specific structures in the brain tune in to one another at certain frequencies. Their rhythmic activity creates brain waves, and the tuning of these brain waves normally allows information to be processed that guides our behavior. But cannabis causes disturbances in systems involved in concentration and memory, the team found.
The primary psychoactive ingredient of cannabis, known as THC, activates cannabinoid receptors, which are found in many brain areas. In the research, the team measured the electrical activity from hundreds of neurons in rats when given a drug similar to THC which also stimulates cannabinoid receptors.
This showed that the effects on individual brain regions were subtle, but brain waves across the hippocampus and prefrontal cortex were completely disrupted. These two brain areas are vital for memory and decision-making, so the rats were no longer able to accurately navigate a maze. Both areas are also involved in schizophrenia.
Findings are published in the Journal of Neuroscience. The authors write that these results show a possible mechanism behind the cognitive impairment caused by cannabis that was described by Dr Frederick T. Melges and his team back in 1970. Dr. Melges called the effect “temporal disintegration,” and described it as “difficulty in retaining, coordinating and serially indexing those memories, perceptions and expectations that are relevant to the goal one is pursuing.”
More recent studies suggest that THC given intravenously to healthy volunteers can induce several psychotic symptoms of schizophrenia, so the authors believe that THC studies be used to model broader aspects of the disease, not just cognitive dysfunction.
Dr. Jones commented, “Marijuana abuse is common among sufferers of schizophrenia and recent studies have shown that the psychoactive ingredient of marijuana can induce some symptoms of schizophrenia in healthy volunteers. These findings are therefore important for our understanding of psychiatric diseases, which may arise as a consequence of ‘disorchestrated brains’ and could be treated by re-tuning brain activity.”
Co-author Michal Kucewicz added, “These results are an important step forward in our understanding of how rhythmic activity in the brain underlies thought processes in health and disease.”
The researchers conclude, “These tools will continue to shed light on the neural mechanisms of working memory and decision making in health and disease.”
A 2012 review of current knowledge shows that the endocannabinoid system in the brain has a major role in schizophrenia. “Data reported so far clearly indicate the presence of a dysregulation in the endocannabinoid system in animal models of psychosis as well as in schizophrenic patients,” the review says.
Its authors, led by Professor Daniela Parolaro of the University of Insubria, Italy, add that animal models suggest that adolescence is “a highly vulnerable age for the consequences of cannabis exposure on different domains (such as cognition and social behavior) that are altered in psychotic disorders.”
They suggest that drugs which target the cannabinoid system are “a new therapeutic possibility for psychotic disorders.” However, they warn that drug studies so far have not had straightforward results, with different types of drug showing different effects.
But despite all these limitations, cannabidiol, a compound found in cannabis that activates cannabinoid receptors, has shown fairly consistent antipsychotic properties in animal tests. Recent studies indicate that cannabidiol may be as effective as antipsychotics in treating schizophrenia.
The benefit of cannabidiol appears similar to that gained from atypical antipsychotic drugs, and so far it is considered a safe and well-tolerated compound. Future studies will need to compare its antipsychotic effects against standard drugs for schizophrenic patients."
I'm actually really interested to try cannabidiol (perhaps mixed with a small amount of other cannabinoids) in the future by prescription for my disorder.
http://psychcentral.com/lib/2012/cannabis-may-cause-schizophrenia-like-brain-changes/
http://jop.sagepub.com/content/26/1/177.short
http://web.lemoyne.edu/~hevern/storiedconduct/files/Cannabis and psychosis.html
http://www.emaxhealth.com/1275/marijuana-use-leads-earlier-psychosis-bipolar-disorder
http://healthland.time.com/2011/02/...er-onset-of-schizophrenia-in-research-review/
http://articles.latimes.com/2007/jul/27/science/sci-marijuana27
http://www.ncbi.nlm.nih.gov/pubmed/15763748
http://www.sciencedaily.com/releases/2007/07/070731125526.htm
Thanks
