A false link between marijuana and mental illness

“The article published today in “Health News” makes the claim that smoking marijuana is “linked” to early onset of mental illness.

However, although the article implies some sort of cause and effect, that conclusion has no scientific basis. In fact, the authors of the study don’t even bother investigating whether marijuana use causes mental illness or if people with mental illness have a higher rate of smoking marijuana than the general public.

If marijuana caused mental illness, then cultures that have a higher rate of marijuana smoking than the U.S. should have a higher rate of mental illness. But in fact, the opposite is true. Cultures with higher rates of marijuana consumption have lower rates of mental illness than the United States. This would indicate that rather than marijuana causing mental illness, as your article implies, it is people with mental illness who are self medicating with marijuana in order to alleviate their symptoms.

This (more correct) reading of the data, however, does not fit the narrative being presented by the politicians who are making their careers by “getting tough” on marijuana smokers, nor does it fit the narrative of the manufacturers of the currently legal psychotropic drugs, like Prozac and Zoloft, who stand to lose billions of dollars if medical marijuana is legalized, and who funnel millions of dollars to those politicians who present their dubious science as fact.

Had your newspaper even taken the time to Google the Archive of General Psychiatry, you would have found that the “study” you cited was conducted by the “Genetic Risk and Outcome in Psychosis (GROUP) Investigators,” who publish only articles against medical marijuana. That alone should raise a red flag to anyone with a basic understanding of scientific research. When someone conducts numerous studies and publishes many articles that all draw the same conclusion, whether the evidence leads to that conclusion or not, the critical eye should suspect some ulterior motive at work. It’s not possible to keep an open mind when you have an axe to grind.”

William Smith, Baltimore

http://articles.baltimoresun.com/2011-02-09/news/bs-ed-marijuana-letter-20110209_1_mental-illness-medical-marijuana-lower-rates

Doubt cast on cannabis, schizophrenia link – ABC Science

“A new study in the UK has cast doubt on the supposed link between cannabis use and schizophrenia.

This latest study, led by Dr Martin Frisher of Keele University, examined the records of 600,000 patients aged between 16 and 44, but failed to find a similar link.

“An important limitation of many studies is that they have failed to distinguish the direction of association between cannabis use and psychosis,” the authors write in the latest edition of the journal Schizophrenia Research.

Not as predicted

Frisher and colleagues compared the trends of cannabis use with general practitioner records of schizophrenia.

They argue if cannabis use does cause schizophrenia, then an increase in cannabis use should be followed by an increase in the incidence of schizophrenia.

According to the study, cannabis use in the UK between 1972 and 2002 has increased four-fold in the general population, and 18-fold among under-18s.

Based on the literature supporting the link, the authors argue that this should be followed by an increase in schizophrenia incidence of 29% between 1990 and 2010.

But the researchers found no increase in the diagnosis of schizophrenia or other psychotic disorders during that period. In fact some of the data suggested the incidence of these conditions had decreased.

“This study does not therefore support the specific causal link between cannabis use and the incidence of psychotic disorders,” the authors say”

http://www.abc.net.au/science/articles/2009/09/01/2673334.htm

Cannabis/schizophrenia link questioned

“The Swiss government is questioning the results of a study showing a link between marijuana use and schizophrenia.

The Zurich University study showed a higher incidence of schizophrenia in the 1990s in the age groups most likely to use cannabis, Swissinfo said Wednesday.

“We know from other experimental studies that cannabis can cause psychosis, but we have now established a clear link to schizophrenia for the first time,” study co-author Wulf Rossler said.

Swissinfo said the Federal Health Office is questioning the report, saying the patients’ drug histories and other medical details remained unknown.

“It does not uncover the medical history of the patients, for instance the consumption of psychotic substances or other factors that could lead to psychotic illnesses,” the health office in a statement.”

http://phys.org/news104659898.html

Minimal Relationship Between Cannabis And Schizophrenia Or Psychosis Suggested By New UK Study

“Last year the UK government reclassified cannabis from a class C to a class B drug, partly out of concerns that cannabis, especially the more potent varieties, may increase the risk of schizophrenia in young people. But the evidence for the relationship between cannabis and schizophrenia or psychosis remains controversial. A new study has determined that it may be necessary to stop thousands of cannabis users in order to prevent a single case of schizophrenia.

Scientists from Bristol, Cambridge and the London School of Hygiene and Tropical Medicine took the latest information on numbers of cannabis users, the risk of developing schizophrenia, and the risk that cannabis use causes schizophrenia to estimate how many cannabis users may need to be stopped to prevent one case of schizophrenia. The study found it would be necessary to stop 2800 heavy cannabis users in young men and over 5000 heavy cannabis users in young women to prevent a single case of schizophrenia. Among light cannabis users, those numbers rise to over 10,000 young men and nearly 30,000 young women to prevent one case of schizophrenia.

That’s just part of the story. Interventions to prevent cannabis use typically do not succeed for every person who is treated. Depending on how effective an intervention is at preventing cannabis use, it would be necessary to treat even higher numbers of users to achieve the thousands of successful results necessary to prevent a very few cases of schizophrenia.

Matt Hickman, one of the authors of the report published last week in the scholarly journal Addiction, said that “preventing cannabis use is important for many reasons – including reducing tobacco and drug dependence and improving school performance. But our evidence suggests that focusing on schizophrenia may have been misguided. Our research cannot resolve the question whether cannabis causes schizophrenia, but does show that many people need to give up cannabis in order to have an impact on the number of people with schizophrenia. The likely impact of re-classifying cannabis in the UK on schizophrenia or psychosis incidence is very uncertain.”

Source:
Amy Molnar
Wiley-Blackwell”

http://www.medicalnewstoday.com/releases/168519.php

Alcohol and cannabis use and mortality in people with schizophrenia and related psychotic disorders.

“The impact of co-morbid substance use on mortality is not well studied in psychotic disorders. The objective of this study was to examine the impact of substance use on mortality in people with psychotic disorders and alcohol and/or drug use.

…In a Cox model, predicted mortality risk was higher in age group 35-55 compared to <35 years and in males, but reduced in cannabis users. Overall five- (3.1% vs 7.5%) and ten-year mortality risk (5.5% vs. 13.6%) was lower in cannabis users than in non-users with psychotic disorders (p = 0.005) in a survival model.

 We observed a lower mortality risk in cannabis-using psychotic disorder patients compared to cannabis non-users despite subjects having similar symptoms and treatments.

 Future research is warranted to replicate these findings and to shed light on the anti-inflammatory properties of the endocannabinoid system and its role in decreased mortality in people with psychotic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/22595870

Cannabinoids and Schizophrenia: Therapeutic Prospects.

“Approximately one third of patients diagnosed with schizophrenia do not achieve adequate symptom control with standard antipsychotic drugs (APs).

The endocannabinoid system (ECS) in the brain plays an important role in maintaining normal mental health.

ECS modulates emotion, reward processing, sleep regulation, aversive memory extinction and HPA axis regulation…

The cannabis plant synthesises a large number of pharmacologically active compounds unique to it known as phytocannabinoids. In contrast to the euphoric and pro-psychotic effects of delta-9-tetrahydrocannabinol (THC), certain non-intoxicating phytocannabinoids have emerged in pre-clinical and clinical models as potential APs.

Since the likely mechanism of action does not rely upon dopamine D2 receptor antagonism, synergistic combinations with existing APs are plausible.

The anti-inflammatory and immunomodulatory effects of the non-intoxicating phytocannabinoid cannabidiol (CBD) are well established and are summarised below.

Preliminary data reviewed in this paper suggest that CBD in combination with a CB1 receptor neutral antagonist could not only augment the effects of standard APs but also target the metabolic, inflammatory and stress-related components of the schizophrenia phenotype.”

http://www.ncbi.nlm.nih.gov/pubmed/23829368

“6”-Azidohex-2″-yne-cannabidiol: a potential neutral, competitive cannabinoid CB1 receptor antagonist… 6″-azidohex-2″-yne-cannabidiol was as potent as cannabidiol in producing surmountable antagonism… it is a competitive cannabinoid CB(1) receptor antagonist…it may be a neutral cannabinoid CB(1) receptor antagonist.”  http://www.ncbi.nlm.nih.gov/pubmed/15033394

 

Could Marijuana Treat Schizophrenia?

“Researchers find cannabidiol is as effective as standard antipsychotic drugs—with fewer side effects.”

A compound found in marijuana can help treat schizophrenia as effectively as standard antipsychotic drugs—and with fewer side effects—according to the results of a new clinical trial, reports The Fix columnist Maia Szalavitz in Time. Researchers at University of Cologne in Germany studied 39 people with schizophrenia, all hospitalized for a psychotic episode. Twenty of the patients were given cannabidiol (CBD), a substance found in marijuana that is associated with its mellowing, anti-anxiety effects (not THC—the main ingredient in marijuana, which has been found to worsen schizophrenia). The other participants were given amisulpride, an antipsychotic medication. At the end of the four-week trial, both groups showed significant clinical improvement in their schizophrenic symptoms. “The results were amazing,” says Daniele Piomelli, professor of pharmacology at the University of California-Irvine and a co-author of the study. “Not only was [CBD] as effective as standard antipsychotics, but it was also essentially free of the typical side effects seen with antipsychotic drugs.” Antipsychotic medications can cause serious, sometimes permanent movement disorders and other side effects such as weight gain and movement problems. In the study, these side effects were observed in those taking amisulpride, but not in those taking CBD. “These exciting findings should stimulate a great deal of research,” says Dr. John Krystal, chair of psychiatry at Yale University School of Medicine, who was not associated with the study. He noted that CBD, in addition to having fewer side effects, also seemed to work better on schizophrenia’s negative symptoms, which are notoriously difficult to treat, including: social withdrawal, blunting of pleasure, and lack of motivation.”

http://www.thefix.com/content/pot-compound-treats-schizophrenia-few-side-effects91717

The endocannabinoid system and its therapeutic exploitation.

Image result for Nat Rev Drug Discov.

“The term ‘endocannabinoid’ – originally coined in the mid-1990s after the discovery of membrane receptors for the psychoactive principle in Cannabis, Delta9-tetrahydrocannabinol and their endogenous ligands – now indicates a whole signalling system that comprises cannabinoid receptors, endogenous ligands and enzymes for ligand biosynthesis and inactivation. This system seems to be involved in an ever-increasing number of pathological conditions. With novel products already being aimed at the pharmaceutical market little more than a decade since the discovery of cannabinoid receptors, the endocannabinoid system seems to hold even more promise for the future development of therapeutic drugs. We explore the conditions under which the potential of targeting the endocannabinoid system might be realized in the years to come.”  http://www.ncbi.nlm.nih.gov/pubmed/15340387

http://www.nature.com/nrd/journal/v3/n9/full/nrd1495.html

Cannabinoids ameliorate impairments induced by chronic stress to synaptic plasticity and short-term memory.

“Repeated stress is one of the environmental factors that precipitates and exacerbates mental illnesses like depression and anxiety as well as cognitive impairments. We have previously shown that cannabinoids can prevent the effects of acute stress on learning and memory.

Here we aimed to find whether chronic cannabinoid treatment would alleviate the long-term effects of exposure to chronic restraint stress on memory and plasticity as well as on behavioral and neuroendocrine measures of anxiety and depression. Late adolescence rats were exposed to chronic restraint stress for two weeks followed each day by systemic treatment with vehicle or with the CB1/2 receptor agonist WIN55,212-2 (1.2 mg/kg). Thirty days after the last exposure to stress, rats demonstrated impaired long-term potentiation (LTP) in the ventral subiculum (vSub)-nucleus accumbens (NAc) pathway, impaired performance in the prefrontal cortex (PFC)-dependent object recognition task and the hippocampal-dependent spatial version of this task, increased anxiety levels, and significantly reduced expression of glucocorticoid receptors (GRs) in the amygdala, hippocampus, PFC and NAc. Chronic WIN55,212-2 administration prevented the stress-induced impairment in LTP levels and in the spatial task, with no effect on stress-induced alterations in unconditioned anxiety levels or GR levels. The CB1 antagonist AM251 (0.3 mg/kg) prevented the ameliorating effects of WIN55,212-2 on LTP and short-term memory. Hence, the beneficial effects of WIN55,212-2 on memory and plasticity are mediated by CB1 receptors and are not mediated by alterations in GR levels in the brain areas tested.

 Our findings suggest that cannabinoid receptor activation could represent a novel approach to the treatment of cognitive deficits that accompany a variety of stress-related neuropsychiatric disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/23426383

Marijuana Compound May Beat Antipsychotics at Treating Schizophrenia

“A certain marijuana compound known as cannabidiol (CBD) can treat schizophrenia as well as antipsychotic drugs, with far fewer side effects, according to a preliminary clinical trial.”

Read more: http://psychcentral.com/news/2012/06/07/marijuana-compound-may-beat-antipsychotics-at-treating-schizophrenia/39803.html