Doctors: Pot Triggers Psychotic Symptoms
By MARIA CHENG
AP Medical Writer
April 30. 2007

LONDON (AP) - New findings on marijuana's damaging effect on the brain show the drug triggers temporary psychotic symptoms in some people, including hallucinations and paranoid delusions, doctors say.

British doctors took brain scans of 15 healthy volunteers given small doses of two of the active ingredients of cannabis, as well as a placebo.

One compound, cannabidiol, or CBD, made people more relaxed. But even small doses of another component, tetrahydrocannabinol, or THC, produced temporary psychotic symptoms in people, including hallucinations and paranoid delusions, doctors said.

The results, to be presented at an international mental health conference in London on Tuesday and Wednesday, provides physical evidence of the drug's damaging influence on the human brain.

"We've long suspected that cannabis is linked to psychoses, but we have never before had scans to show how the mechanism works," said Dr. Philip McGuire, a professor of psychiatry at King's College, London. the rest