Teenage cannabis use and schizophrenia

With the growing wave of legalizing marijuana use across the US, it is important to fully understand the possible consequences of expected increase in it's unrestricted use, specially amongst the youth. A group of scientist at the Feinberg School of Medicine and Northwestern Memorial Hospital have conducted a study which has found a link between teenage Marijuana (Cannabis) use and schizophrenia. This study was published by Schizophrenia Bulletin

The brains of teenagers smoking cannabis daily for about three years showed significant structural changes affecting memory. Some of those changes appear very similar to those seen in the brains of schizophrenics.These youngsters also performed badly when tested on memory tasks, indicating poor memory functioning.


As reported by Marla Paul for Northwestern University on Futurity;

This is the first study to target key brain regions in the deep sub-cortical gray matter of chronic marijuana users with structural MRI and to correlate abnormalities in these regions with an impaired working memory.
Working memory is the ability to remember and process information in the moment and—if needed—transfer it to long-term memory. Previous studies have evaluated the effects of marijuana on the cortex, and few have directly compared chronic marijuana use in otherwise healthy individuals and individuals with schizophrenia.

According to the lead study author Mathew Smith an assistant research professor in psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine; 

“The study links the chronic use of marijuana to these concerning brain abnormalities that appear to last for at least a few years after people stop using it. With the movement to decriminalize marijuana, we need more research to understand its effect on the brain.”

 But in contrast to these findings another study conducted at the Institute of Psychiatry at King's College London, has shown a genetic link between cannabis use and schizophrenia. Kate Kelland  reports for Reuters that;

The results chime with previous studies linking schizophrenia and cannabis, but suggest the association may be due to common genes and might not be a causal relationship where cannabis use leads to increased schizophrenia risk. 

 "We know that cannabis increases the risk of schizophrenia. Our study certainly does not rule this out, but it suggests that there is likely to be an association in the other direction as well – that a pre-disposition to schizophrenia also increases your likelihood of cannabis use," said Robert Power, who led the study at the Institute of Psychiatry at King's College London.

But what become evident from both these recent studies is the clear connection between adolescent use of cannabis and the development of schizophrenia. Therefore it is important for parents to discourage their children from getting swept up in this growing wave of legal recreational use of marijuana. We need to educate ourselves and our children on the very real dangers and consequences of indiscriminate use of marijuana.
 



References:

Teen marijuana use linked with schizophrenia (Futurity-January 3, 2014)

Study finds genetic links between schizophrenia and cannabis use (Reuters-June 24, 2014)

Cannabis-Related Working Memory Deficits and Associated Subcortical Morphological Differences in Healthy Individuals and Schizophrenia Subjects  (Schizophrenia Bulletin-December 15, 2013)

Genetic predisposition to schizophrenia associated with increased use of cannabis (Molecular Psychiatry-June 24, 2014)

Vitamin E and Selenium supplements may increase risk of cancer

With this increasing obsession with fitness and health the use of supplements such as vitamins, minerals, and herbal has increased exponentially. The increased efforts to stay healthy are good news but the fact that a huge majority of individuals do not even know what supplement to take or not to take, many end up losing any benefit and incur more damage to their health then advantage.

Recent clinical trials have shown that the unnecessary use of certain dietary supplements can lead to far more serious problems then known before. Such a study conducted in the US has shown that the high levels of the mineral Selenium can lead to a 91% increased risk for high grade cancer.
According to the the study leader Dr. Alan Kristal (Fred Hutchinson Cancer Research Centre, Seattle)"These supplements are popular – especially vitamin E – although so far no large, well-designed and well-conducted study has shown any benefits for preventing major chronic disease.
"Men using these supplements should stop, period. Neither selenium nor vitamin E supplementation confers any known benefits, only risks."

This adverse effect appeared only when men with already high levels took the selenium supplement and not in men who originally had low levels. It was also noted that Vitamin E also increased the risk of cancer almost doubling it in men who had low level of selenium.

This study was a follow-up of Select (selenium and vitamin E cancer prevention trial), which originally recruited more than 35,000 men to see if the supplements could help prevent prostate cancer. The main goal of the trial was to prove whether selenium and vitamin E supplements actually prevented prostrate cancer. It was concluded "SELECT was initially planned for a minimum of seven years and a maximum of 12 years of participants taking supplements, plus follow-up observation after the men finished taking their supplements. However, the independent Data and Safety Monitoring Committee (DSMC) for the trial met on September 15, 2008, to review SELECT study data and found that selenium and vitamin E, taken alone or together did not prevent prostate cancer. The committee also determined that it was unlikely selenium and vitamin E supplementation would ever produce a 25 percent reduction in prostate cancer incidence, as the study was designed to show. Based on their recommendation, with SWOG and NCI agreement, SELECT participants were told in October 2008 to stop taking their study supplements." (National Cancer Institute)

The Select trial suggested that Vitamin E intake may have more detrimental effects then initially thought, whereas the outcome of overuse of selenium was still disputed hence the follow up study.     "In 2011, data showed that men taking vitamin E alone had a significantly increased risk of prostate cancer, but men taking vitamin E plus selenium did not.  If men had low selenium levels at the start of the trial, the selenium supplement may have counteracted a negative effect of the vitamin E supplement." (Select study - NCI)

The results of this follow-up study have shown a clear relation between selenium and vitamin E supplements and the increased risk of prostrate cancer.
"In an analysis published in 2014, men who had high levels of selenium at the start of the trial, as assessed by measures of selenium in their toenail clippings, had almost double the chance of developing a high-grade prostate cancer if they took the selenium supplement compared to men with low levels of selenium at the start of the trial.  This finding was unexpected, as previous studies had shown that men with low levels of selenium had an increased risk of prostate cancer that was reduced with supplements (11, 12).  Additionally, men with low levels of selenium at the start of the trial had double the chance of developing a high-grade prostate cancer if they took the vitamin E supplement."
(National Cancer Institute)

A detailed article on the latest results was published on February 21st 2014 in The Guardian, titled

Some vitamin supplements raise risk of cancer in men, research shows.

P.S:

References:

Selenium and Vitamin E Cancer Prevention Trial (SELECT) (National Cancer Institute)
Some vitamin supplements raise risk of cancer in men, research shows. (The Guardian)