Science And Technology Desk

GENE GLITCHES LINK POT WITH SCHIZOPHRENIA

OKAYAMA, Japan -- Genetic anomalies tied with marijuana-activated brain
chemicals appear linked to schizophrenia, Japanese researchers report.

"This result provides genetic evidence that marijuana use can result in
schizophrenia or a significantly increased risk of schizophrenia," lead
researcher Hiroshi Ujike, a clinical psychiatrist at Okayama University,
told United Press International.

Schizophrenia is one of the greatest mental health challenges in the world,
affecting roughly one of every 100 people and filling about a quarter of
all hospital beds in the United States. For years, clinical scientists have
known that abusing marijuana, also known as cannabis, can trigger
hallucinations and delusions similar to symptoms often found in
schizophrenia. Prior studies also show that cannabis used before age 18
raises the risk of schizophrenia six-fold.

The hallucinogenic properties of marijuana, the researchers explained, are
linked to a biochemical found abundantly in the brain. The chemical, called
cannabinoid receptor protein, studs the surfaces of brain cells and latches
onto the active chemical within marijuana known as THC.

"These sites are where marijuana acts on the brain," Ujike said.

Ujike and his team examined the gene for the marijuana receptor in 121
Japanese patients with schizophrenia and an average age of 44. When they
compared this gene in schizophrenics with the same gene in 148 normal men
and woman of the same average age, they found distinct abnormalities in DNA
sequences called nucleotides among the schizophrenics. Some of their
nucleotides in the marijuana receptor gene appeared significantly more
often than normal while others appeared less frequency.

"This finding is the first to report a potential abnormality of the
cannabinoid system in schizophrenia," said clinical neuroscientist Carol
Tamminga at the University of Maryland in College Park. "The importance of
a finding here cannot be overstated, in that it would form a tissue target
for drug development and allow targeted treatments to emerge for the illness."

It appears malfunctions in the brain's marijuana-linked circuitry may make
one vulnerable to schizophrenia, Ujike said. This holds especially true for
a condition called hebephrenic schizophrenia, which is marked by
deterioration of personality, senseless laughter, disorganized thought and
lack of motivation. These symptoms are similar to psychotic behavior
sometimes triggered by severe cannabis abuse, which could mean the
marijuana receptors in schizophrenics are far more active than they should be.

Ujike stressed there is no evidence yet these genetic abnormalities can
affect how the marijuana receptor actually acts in the brain. "We would
also like to replicate our findings with different ethnic populations and
more people," he added.

The researchers described their findings in the scientific journal
Molecular Psychiatry.