'REEFER MADNESS' VINDICATED: POT USE, PSYCHOSIS LINKED

Casual Tokers Raise Risk 40%, Study Says

LONDON, England (AP) -- Using marijuana seems to increase the chance
of becoming psychotic, researchers report in an analysis of past
research that reignites the issue of whether pot is dangerous.

Some experts say governments should now work to dispel a misconception
that marijuana is a benign drug.

The new review suggests that even infrequent use could raise the small
but real risk of this serious mental illness by 40 percent.

Doctors have long suspected a connection and say the latest findings
underline the need to highlight marijuana's long-term risks. The
research, paid for by the British Health Department, is being
published Friday in medical journal The Lancet.

"The available evidence now suggests that cannabis is not as harmless
as many people think," said Dr. Stanley Zammit, one of the study's
authors and a lecturer in the department of psychological medicine at
Cardiff University.

The researchers said they couldn't prove that marijuana use itself
increases the risk of psychosis, a category of several disorders with
schizophrenia being the most commonly known.

There could be something else about marijuana users, "like their
tendency to use other drugs or certain personality traits, that could
be causing the psychoses," Zammit said.

Marijuana is the most frequently used illegal substance in many
countries, including the United Kingdom and the United States. About
20 percent of young adults report using it at least once a week,
according to government statistics.

Zammit and colleagues from the University of Bristol, Imperial College
and Cambridge University examined 35 studies that tracked tens of
thousands of people for periods ranging from one year to 27 years to
examine the effect of marijuana on mental health.

They looked for psychotic illnesses as well as cognitive disorders
including delusions and hallucinations, bipolar disorder, depression,
anxiety, neuroses and suicidal tendencies.

They found that people who used marijuana had roughly a 40 percent
higher chance of developing a psychotic disorder later in life.

Zammit said the risk of developing schizophrenia for most people is
less than 1 percent. The prevalence of schizophrenia is believed to be
about five in 1,000 people. The researchers estimate that about 800
new cases of psychosis could be prevented by reducing marijuana use.

The scientists found a more disturbing outlook for "heavy users" of
pot, those who used it daily or weekly: Their risk for psychosis
jumped to a range of 50 percent to 200 percent.

One doctor noted that people with a history of mental illness in their
families could be at higher risk. For them, marijuana use "could
unmask the underlying schizophrenia," said Dr. Deepak Cyril D'Souza,
an associate professor of psychiatry at Yale University, who was not
involved in the study.

Dr. Wilson Compton, a senior scientist at the National Institute on
Drug Abuse in Washington, called the study persuasive.

"The strongest case is that there are consistencies across all of the
studies," and that the link was seen only with psychoses -- not
anxiety, depression or other mental health problems, he said.