Wednesday, March 02, 2011

Cannabis 'doubles risk of psychotic episodes'

This finding seems sound

Using cannabis in one's youth almost doubles the risk of having psychotic episodes like paranoia and hallucinations, a study has found. A team of international researchers followed the lives of almost 2,000 young Germans, who began with no history of psychosis, for more than a decade.

They discovered that youngsters who started smoking the drug at college age were 90 per cent more likely to have psychotic symptoms in their mid-20s.

In the study, cannabis users were defined as those who had used the drug at least five times between 18 and 21. Rates of psychotic episodes between users and non-users at the age of 26 were then compared. Other factors known to affect likelihood of psychosis, such as childhood trauma, class, and growing up in an urban environment, were accounted for.

The authors, led by Rebecca Kuepper, a research psychologist at Maastricht University in The Netherlands, concluded: "This 10 year follow-up study showed that incident cannabis use significantly increased the risk of incident psychotic experiences."

The scientists believe that exposure to THC, the main psychoactive component in cannabis, makes the brain more susceptible to psychotic episodes.

The study also found that a rise in psychotic episodes followed cannabis use, rather than the other way around, disproving the theory that the relationship between the two was nothing more than people prone to psychosis self-medicating.

Cannabis was downgraded from a class B to a class C drug in 2004. Critics said that gave young people the impression it had been decriminalised. The decision was reversed in 2009.

Sir Robin Murray, professor of psychiatric research at Kings College London, said: "This study adds a further brick to the wall of evidence showing that use of traditional cannabis is a contributory cause of psychoses like schizophrenia."

But he said it did not "address the important question of whether skunk and other potent types of cannabis carry a higher risk of psychosis than traditional resin and marijuana".

Peter Kinderman, professor of clinical psychology at Liverpool University, said the study "offers more evidence that cannabis use is a risk factor for psychosis and recommends a cautious and thoughtful approach to cannabis legislation".


Siesta can protect against high blood pressure

This is a very limited study much in need of replication if its conclusions are to be accepted as generally true. The sampling (or non-sampling) is ludicrous for a start. Findings from available groups of students often do not generalize

Having an afternoon nap can help protect against heart disease, a study has suggested.

Researchers say that having a 45 minute catnap helps lower a person's blood pressure more quickly after a stressful event.
And with the average night's sleep now two hours shorter than it was 50 years ago, researchers claim having a siesta provides a simple way of improving cardiovascular health.

Researchers from Allegheny College in Pennsylvania, USA, conducted an experiment which saw 85 healthy students split into two groups.
One group was allotted 60 minutes each day during which they could sleep, the other did not sleep during the day. Participants in the experiment, the findings of which are published in Springer's International Journal of Behavioural Medicine, were then asked to complete a complex mental subtraction sum designed to raise blood pressure.

Students who napped for between 45-60 minutes were found to have significantly lower blood pressure rates during the post-activity recovery phase than those who had not slept. A questionnaire given to participants also saw those who had a siesta reporting much less sleepiness than those who hadn't.

Study authors Ryan Brindle and Sarah Conklin PhD, said the experiment proved the "recuperative and protective" benefits of a daytime snooze. They said: "Our findings suggest that daytime sleep may offer cardiovascular benefit by accelerating cardiovascular recovery following mental stressors.

"Further research is needed to explore the mechanism by which daytime sleep is linked with cardiovascular health and to evaluate daytime sleep as a recuperative and protective practice, especially for individuals with known cardiovascular disease risk and those with suboptimal sleep quality."


No comments: