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The Office of Technology Assessment reached the following
conclusion about marijuana's abuse potential in 1993:
"While marijuana produces a feeling of euphoria in humans,
in general, animals will not self-administer THC in controlled
studies. Also, cannabinoids generally do not lower the threshold
needed to get animals to self-stimulate the brain reward system,
as do other drugs of abuse."(20)
The conclusion of OTA is widely acknowledged in the pharmacological
literature. Billy Martin has written extensively on marijuana
related research, and conducts research at the Medical College
Of Virginia. In a paper with colleague Mary Abood, Martin
reports in 1992 that:
"While self-administration of drugs has been taken as
an indication of psychological dependence and/or abuse potential,
few reports claim to have established experimental models
for self administration of D9-THC . . . This observation suggests
limited potential for development of . . . limited psychological
dependence due to the weak reinforcing properties of D9-THC."(21)
Miles Herkenham conducts research for the National Institute
of Mental Health on the mechanism of action of marijuana's
effects on the brain. Also in a 1992 paper, Herkenham's review
of the literature produces this comment:
"Animals generally will not self-administer D9-THC. Cannabinoids
did not lower the threshold for electrical self-stimulation
in one study. In another study they did, but apparently both
this phenomenon and the enhancement of basal dopamine efflux
from the [nucleus accumbens] by D9-THC are strain-specific,
occurring only in Lewis rats."(22)
According to Iwamoto and Martin, one of the criticisms
of making self-administration a preeminent test of abuse potential
is that:
"The mechanisms underlying self-administration behavior
in animals are not well-understood."(23)
Another problem is presented by possible anomalies.
"There are drugs, however, which are used by humans that
are not self-administered by animals and include LSD, mescaline,
DOM and [marijuana]."(24)
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