杏吧原创

CHOMPING on betel nut, one of the world鈥檚 most popular habits, might help
people suffering from schizophrenia. Researchers studying a Pacific island
community have found that chewing the nut alleviates the worst symptoms of the
illness.

Betel nut, the fruit of the areca palm, is the most used drug worldwide after
nicotine, alcohol and caffeine. In Africa, Asia and across the Pacific the nut
is mixed with slaked lime, wrapped in a leaf, chewed and spat out, leaving users
with reddish-black stained teeth.

Roger Sullivan from the University of Auckland and his colleagues
investigated whether chewing the nut, which is thought to be a mild stimulant,
has any effect on the symptoms of schizophrenia. They travelled to the Republic
of Palau in the Western Pacific, where two in every hundred islanders suffer
from the disease, twice the rate elsewhere. Studies of six generations of
Palauan families have revealed a gene on chromosome 2 that is linked to the
illness, and which has spread through the small isolated population.

About 70 per cent of Palauans chew betel nut, but among schizophrenics the
rate is even higher鈥攁round 80 per cent. Sullivan鈥檚 team examined 70
schizophrenic patients and found that on a standard clinical scale of symptoms,
sufferers who chewed more than 10 nuts a day had far milder
symptoms鈥攈allucinations, delusions and depression鈥攖han those without
the habit. For sufferers who weren鈥檛 on any medication, the difference in
symptoms between chewers and non-chewers was even more marked.

Sullivan believes that alkaloids in the nut are responsible for its effects.
Betel nut contains the powerful alkaloid arecoline, which is similar to the
neurotransmitter acetylcholine. Raising the level of acetylcholine in the brain
is known to reduce the amount of another neurotransmitter, dopamine, and there
has been some success in treating schizophrenia by blocking the action of
dopamine. Sullivan suggests that the betel nut alkaloid might indirectly reduce
dopamine production.

He is hopeful that their work could lead to a new treatment for
schizophrenia. But he cautions that their findings need to be repeated in
clinical trials. Tracking the progress of the illness in both chewers and
non-chewers will also show if there is a long-term benefit, he says.