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)