This legislation is called 'the Controlled Substance Analogue Enforcement Act of 1986' and is part of Public Law 99-570. It was signed into law on October 27, 1986, just days before the national elections, and the news and ramifications of it have been largely lost in the noise and drama of the political events of the time. I personally believe that this law presents a shameful barrier to a very important segment of scientific research.
Let me dissect this law into its two major parts. What is an analogue? And what is the behaviour, involving an analogue, that is criminal?
According to this law, a drug is an analogue if it meets any one of the following criteria:
First, the chemical structure of the drug is considered. The compound is an analogue if its structure is substantially similar to the structure of any listed Schedule I or II drug. Just what are the structures of the drugs that are contained in these two schedules? You can find a complete spectrum of functional groups. All four types of amines are present; primary amines, secondary amines, tertiary amines, and quarternary ammonum salts. All three types of alcohols are present; primary alcohols, secondary alcohols, and tertiary alcohols. There are acids, esters, ethers, amids, ketones, and nitriles.
There are examples of all the most common heterocyclic ring systems, such as pyridines, piperidines, pyrrolidines, indoles, imidazoles, morpholines, thiophenes, furans, pyrans, quinazolines, dioxoles, oxazolines, pyrimidines, and purines. And of course, there are simple benzene-ring aromatic compounds and there are simple non-benzene-ring aliphatic compounds including cyclopropyl rings, cyclobutyl rings, cyclopentyl rings, and cyclohexyl rings. One would be hard put to find a structure of any drug, anywhere, which could not be argued by some person, somewhere, as being in some way structurally related to a Schedule I or a Schedule II drug.
And what was the reason for the use of the intentionally vague phrase "substantially similar"? There is a term in rhetoric knows as a disclaimer, a word introduced as a hedge or a qualification, a word chosen to allow a certain freedom of interpretation. Words or phrases such as almost, probably, approximately, in a few days, in two weeks at the latest, are disclaimers. There is a measured ambiguity in the phrase "similar to" and there is a measured ambiguity in the phrase "substantially the same as." But what is to be inferred from "substantially similar"? Suddenly, the exactness, the precision of the original Controlled Substances Act, with its explicitly named drug targets, had been totally compromised.
A second, independent definition of an analogue deals with its pharmacological action. A drug is to legally considered as an analogue if it has a stimulant, depressant, or hallucinogenic action that is substantially similar to that of a Schedule I or Schedule II drug. In short, any drug which affects the CNS (central nervous system) in any of these ways, or in ways that could be construed as being "substantially similar" to those evoked by a scheduled drug, becomes an analogue within this legal definition. Again, the vague double disclaimer "substantially similar" must be reckoned with as part of the description.
A third definition is an extension of this, and involves the way a drug is represented. If a material is intentionally represented as having a stimulant, depressant, or hallucinogenic action that is substantially similar to that of a Schedule I or Schedule II drug, it becomes an analogue.
It is generally accepted that if two of these three definitions are met then the chemical or drug in question becomes a controlled substance analogue. The law explicitly states that there are four criteria, any of which will exclude it from becoming an analogue; if it is already a controlled substance, if it has an approved drug application, if a particular person has an exemption allowing him investigational use of that drug in question, or it is not intended for human consumption - Alexander shulgin; TIHKAL