among women. But according to other
data, during the time when usage was
thought to have grown most (1996 to 2005),
the number of new schizophrenia cases re-
mained stable or declined. “These findings
strongly suggest that cannabis use does
not cause schizophrenia,” the center’s re-
port notes.
Another speaker at the Berlin confer-
ence—Beat Lutz, a neurochemist at the
University of Mainz—described the mech-
anisms by which the drug might produce
deleterious effects in a young person’s
brain. The main psychoactive compound
in marijuana, THC, disrupts the normal
flow of signals among brain cells—a pro-
cess normally regulated by chemicals
called endocannabinoids.
These compounds occur naturally in the
body and activate a type of cellular docking
site (called the cannabinoid type 1, or CB1,
receptor) to “act like a circuit breaker,” Lutz
says, keeping the brain’s level of signaling
activity or “excitation” within a normal
range. Too little endocannabinoid signal-
ing results in excessive excitation of the
nervous system, and this can promote anx-
iety disorders, impulsivity and epilepsy.
Too much activity has the opposite effect
and can promote depression, for example.
Upsetting the information flows regulated
by the endocannabinoid system has also
been linked to psychosis.
THC acts differently from endocannabi-
noids. It does not break down rapidly in the
body the way natural endocannabinoids do,
Lutz says, noting this sustained activation
causes serious wide-ranging disturbances in
the brain. Low doses of THC may reduce
anxiety but high doses can heighten it, and
chronic overstimulation of CB1 receptors by
THC shuts down the body’s natural endo-
cannabinoid signaling system by eliminat-
ing the CB1 receptors from neurons, Lutz
adds. In addition, new research reveals mi-
tochondria—the organelles within cells thatgenerate energy for cellular metabolism—
also have CB1 receptors. THC inhibits mito-
chondrial activity, reducing the cells’ vital
energy supply, he says, citing a 2016 paper
published in Nature. Perhaps most critically,
he believes THC’s disruption of endocanna-
binoid signaling in the early teen brain can
hinder key neurodevelopmental processes
that involve the CB1 receptors, thereby im-
pairing brain communication permanently.
Recent research on marijuana is starting
to address the type of questions that might
ordinarily be revealed via lengthy clinical
trials during the development of a phar-
maceutical. This process is occurring as
the legalization bandwagon picks up speed.
Marijuana is increasingly taking a placeMarijuana is increasingly taking a place
alongside Johnny Walker and Yellow Tail
on the credenza—no longer stashed away
in a drawer within.