Introduction 3fect of some drugs. If a drug failed to produce physical symptoms associated
with addiction, the substance was classified as nonaddictive. In the 1980s,
however, some researchers began arguing that addiction could exist without
associated physical symptoms, that mental craving alone was enough to
power addiction.^1 An important boost to acceptance of that concept came in
1987 when the American Psychiatric Association declared that “cocainede-
pendence” did not require physical dependence for diagnosis.^2 The APA
stated, “Continuing use ofcocaineappears to be driven by persistent craving
and urges for the substance rather than attempts to avoid or alleviate with-
drawal symptoms.”^3 That approach yielded a broader understanding: that
people could be addicted to things other than drugs, a new and controversial
concept but one that was becoming more accepted as the twenty-first century
began.
Regardless of whether addiction can be more of a mental process than a
physical one, the likelihood of a user developing a harmful relationship with
drugs is greater with some substances than with others. The harm may be
physical. The harm may be disruption of a user’s life. Experience shows, for
example, thatcocaineis far more risky to use thancaffeine.
Some drugs can be used so much that they and a person’s body develop
what may be called a physical resonance. That is not a standard drug abuse
term, but it communicates the concept more vividly than other terminology.
Resonancemeans that an individual’s body has adapted to the drug in such a
way that stopping use of the drug makes a person feel ill. Symptoms depend
on the drug and can range from a runny nose to convulsions. Not all drugs
can produce such a state, but those that can are traditionally called addictive.
Indeed, appearance or nonappearance of an “abstinence” or “withdrawal”
syndrome of illness upon sudden end to drug dosage used to be considered
a definitive test of whether a drug is addictive and whether a user is an addict.
Some specialists might use the termneuroadaptationfor the mechanism that
creates resonance, but here more conservative language that asserts less about
roles of the brain and nervous system will be used.
Resonance is typically, and somewhat misleadingly, called “dependence”
by many persons. An addict who temporarily feels sick upon stopping a drug
but who later feels better is not really “dependent” on it, in the ordinary
dictionary sense of that word’s meaning. Granted, physical dependence upon
a drug is possible, in the dictionary sense, regardless of whether the under-
lying mechanism is neuroadaptation. An example is a diabetic who needs
insulin. Cutting off insulin supply would make the diabetic sicker and sicker,
so the person truly is dependent on the drug. Its presence is necessary for
good health. Normally, however, that is not what is meant by saying a drug
abuser is dependent on a substance; rather, one means the abuser will feel
temporarily ill if dosage suddenly stops. Nonetheless, some drug addictions
can involve the dictionary meaning of dependence. For example, personsex-
tremelyaddicted to alcohol or barbiturates can die if cut off from their supply.
Death typically comes from cascading problems culminating in convulsions.
That dismal outcome is uncommon but possible. In addition,dependenceis
sometimes used in contexts making it synonymous withaddiction, perhaps
referring to persons undergoing treatment to break dependence on some drug