Usdin and Efron (1972) listed 1555 known psychoactive drugs, and Glenn (1974) found that over 60 psychoactive drugs were
included in various surveys of illegal drug use. Obviously, even a specialist in psychopharmacology cannot be familiar with
all 1555 drugs. Even the 60 drugs identified by Glenn are too numerous to commit readily to memory. A classification scheme
is necessary to order the drugs and make them comprehensible.
Canada's Commission of Inquiry into the Non-Medical Use of Drugs (1970) has stated that ' 'Drug classifications based on
a variety of different considerations have been developed and there appears to be little agreement as to the optimal scheme
for ordering the universe of biologically active substances." Since drugs can reasonably be ordered along a variety of dimensions,
choosing one of these dimensions as the basis for categories is an arbitrary decision based on the back¬ground and needs of
the categorizer. Existing schemes have used bases such as clinical utility, molecular structure, effects on the central nervous
system, le¬gality, and hazard potential to categorize drugs. Each categorization is well suited to particular backgrounds
and purposes but is too specific to that background or pur¬pose to be of much use in a general textbook.
A more meaningful and useful categorization could be based on the availability and sources of psychoactive drugs. It would
incorporate legal categories along with other relevant social categories; reflect commonalities in the usage patterns of drugs
grouped together and differences in usage patterns among categories; and reflect societal norms and public attitudes more
accurately than other categorizations.
The categorization used in this text is a modification of those proposed by Miller (unpublished) and used in his work as
Director of the Drug Information Center of the University of Oregon. We have renamed one of Miller's five categories, and
society's two most widely used, misused, and abused drugs have been classified by themselves. For a more extensive discussion
of this categoriza¬tion, see Duncan and Gold (1978) and Gold, Duncan, and Sotherland (1980).
The herbal drugs are plant substances that have drug effects and whose use m not generally regulated by law. These
substances generally require little or no processing after the plants are gathered. Although they may be processed and sold
commercially, it is possible for the consumer to prepare the drug for use if it can be grown locally. Nutmeg, catnip, mandrake,
and fly agaric are herbal drugs.
Over-the-counter drugs are commercially produced drugs that may be pur¬chased legally without a prescription. These
drugs are also known as proprietary drugs. Aspirin, No-Doz®, Nytol®, and Sominex® are widely recognized examples.
Prescription drugs are commercially produced drugs that can be legally sold or dispensed only by a physician or
on a physician's order. They are like over-the-counter drugs in that they are manufactured by pharmaceutical companies, but
they differ in that the decision to use these drugs is legally vested in a licensed physician, not in the user. Examples of
these drugs include Benzedrine®, Seconal®, Valium*. Thorazine®, and codeine.
Unrecognized drugs are commercial products that have psychoactive drug effects but are not usually considered drugs.
These substances are not generally regulated by law except insofar as standards of sanitation and purity are required. Ray
(1978) has called these the "non-drug drugs." Coffee, tea, cola drinks, and! cocoa are examples. Many glues, solvents, and
spray can propellants can also be regarded as unrecognized drugs.
Tobacco is not generally considered a drug and thus could be classed as am unrecognized drug. Tobacco, however,
holds such a distinct position in terms of I usage patterns, economic importance, and health consequences that it merits a
category to itself. Tobacco takes various forms—cigarettes, cigars, pipe tobacco, chewing tobacco, and snuff.
Alcohol also seems to merit its own category, although it, too, could be included in the unrecognized drugs. Alcohol,
in forms such as beer, wine, and distilled liquor, is one of the most widely used drugs in our society. It is regarded by
many experts as the most commonly abused drug in our society.
When people use the word "drug," most often they are referring to illicit drugs.These are the drugs whose sale,
purchase, or use is generally prohibited by law. Criminal penalties usually apply to violators of these laws. Heroin, cocaine,
marijuana, LSD and PCP are the major examples of this category.