Excerpted from "A Protocol for the Evaluation of New Psychoactive Drugs in Man" by Alexander T. Shulgin, L. Ann Shulgin, and Peyton Jacob, III, published in Methods and Findings in Experimental and Clinical Pharmacology 8(5): 313-320, 1986.

- There is no effect noted, of any nature, that can be ascribed to the drug in question.

+/- There is a move away from baseline, but there is not necessarily a conviction that it is drug-related.

+1 There is a real effect, and the duration but not the nature of the content can be discerned. The "alert" has progressed into something unmistakable.

+2 There is an unmistakable effect, and both the duration and the nature of the effect can be stated. At +2, one might be able to answer a telephone sensibly, but would most probably choose not to attempt to do so. One could drive a car with much care, but would wisely choose to do so only in a life-and-death emergency. Cognitive factors are largely intact, and much of the drug's effect could be suppressed if the need should arise.

+3 This is the level of maximum intensity of drug effect. The full potential of the drug has been realized. Its character can be spelled out and the chronological patterns to be expected are defined.

+4 A special designation for "peak experience" in the terminology of Abe Maslow. This is a serene and magical state which is largely independent of what drug is used, if a drug at all, and moreover, cannot be repeated at will with a repetition of the experiment. It is the extraordinary place, that one-of-a-kind, mystical or religious experience that will never be forgotten. This is not to imply in any way that it is more than, or comparable to, the +3. It is simply in a class by itself, and has no suggestion of quantitative value.