Pubdate: Mon, 30 Jun 2014
Source: Albuquerque Journal (NM)
Copyright: 2014 Albuquerque Journal
Contact:  http://www.abqjournal.com/
Details: http://www.mapinc.org/media/10
Author: Geoffrey Mohan, Los Angeles Times
Page: C2

REEFER MADNESS: STUDY LOOKS AT POT, PSYCHOSIS

Does marijuana smoking cause psychosis? Or could psychosis drive pot
smoking?

If you believe the panned and parodied 1936 film "Reefer Madness,"
smoking weed will make one crazy and drive you to a life of crime.

Medical science has taken the question seriously, however, and found a
strong link between schizophrenia symptoms and cannabis use in many
large-scale, peer-reviewed studies. Data from four such studies
suggest that cannabis use doubles the likelihood of developing a
psychotic illness later in life.

But a few small studies have flipped the direction of causation,
suggesting that a genetic predisposition to schizophrenia (a disease
marked by psychotic episodes such as hallucination) is itself a risk
factor for smoking pot. That might explain why pot use is perennially
high (pardon the pun) among those diagnosed with schizophrenia.

A European research team led by Kings College, London, suggests that
at least part of the reason schizophrenic symptoms and pot smoking
overlap may lie in shared genetic markers. Their study was published
online in the journal Molecular Psychiatry.

The results could influence debate over the legalization of marijuana
for medical and recreational use.

Researchers studied 2,082 people, about 49 percent of whom reported
having smoked pot. They analyzed the participants' genome, looking for
known variations that have been associated with schizophrenia. They
found that those with the strongest genetic profile for schizophrenia
risk also were more likely to use cannabis, and to use it in greater
quantities.

Madness, they suggest, may lead to reefer.

The researchers do not rule out an independent path linking marijuana
use to subsequent psychotic episodes, but suggest the overlap between
the two is at least partially a two-way street.

"We know that cannabis increases the risk of schizophrenia," lead
author Robert Power, a psychiatry researcher at Kings College, said in
a statement. "Our study certainly does not rule this out, but it
suggests that there is likely to be an association in the other
direction as - that a predisposition to schizophrenia also increases
your likelihood of cannabis use."

The authors caution that the directional link between reefer and
madness may lie in a mix of genetic risk and environmental factors.

There could be other confounding factors in the study as well, they
acknowledge. Researchers relied on a previous genome-wide risk
assessment that identified slight genetic variations associated with
schizophrenia. But that study's schizophrenia sample was likely to
have unintentionally included many more pot smokers than would be
expected in the general population, and thus may have lumped some
genetic markers for pot-smoking with those associated with
schizophrenia, the authors note.

In other words, there may have been some reefer mixed with their
madness.
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