As with most drugs, the larger the dose taken, the greater the psychopharmacologic effect. Isbell et al. (1967) noted that clinical syndromes vary from a mild euphoric feeling of relaxation at low doses (25 micrograms per kilogram) to an intensive hallucinogenic-like experience at high doses (250 micrograms per kilogram).
ROUTE OF ADMINISTRATION
A second factor which influences the effect experienced by the user is the manner in which the substance is consumed. That is, whether it is smoked, swallowed or injected.
Isbell et al. (1967) demonstrated that smoked material is two and a half to three times as effective as orally consumed marihuana in the form of a 95% ethanolic solution in producing equivalent physiologic and subjective effects.
In addition, the oral time-action curve is extended with onset of symptoms one-half to one hour after administration. A peak effect is reached in two to three hours and the effect persists for three to five hours at low doses and six to eight hours at larger doses (Hollister et al., 1968; Isbell, et -al., 1967; Lemberger et al., 1971; Perez-Reyes, and Lipton, 1971).
In general, the effects produced by ingested THC or ingested marihuana extract are comparable to those produced by nearly one-third the amount of smoked and inhaled THC or marihuana (Hollister, 1971).