The DSM describes many substance-related disorders, which
occur when a person is intoxicated by, withdrawing from, using, abusing, or
dependent on one or more drugs. Two common types of substance-related disorders are
substance abuse and substance dependence.
Substance Abuse
The DSM defines substance abuse as a
maladaptive pattern of drug use that results in repeated negative consequences
such as legal, social, work-related, or school-related problems. A drug abuser
may even use drugs in situations in which it is physically dangerous to do so.
Substance Dependence
Substance dependence, or drug addiction, involves continuing
to use a drug despite persistent physical or psychological costs. A person who
is addicted to drugs may make several unsuccessful attempts to give up the drug
and may even develop tolerance for the drug. Tolerance is the
gradual need for more and more of the drug to get the same effect. The person
may also experience withdrawal symptoms such as sweating, nausea,
muscle pain, shakiness, and irritability when he or she stops taking the
drug.
Etiology of Substance-Dependence
Many researchers believe biology and environment interact to produce
substance dependence.
Biological Influences
Several lines of research have examined genetic predispositions to
drug dependence. Researchers think there may be a genetic predisposition to
one particular type of alcoholism: the type that begins in adolescence and
that is associated with impulsive, antisocial, and criminal behavior. With
other types of alcoholism, many genes may interact to play a role.
Genes may influence traits such as impulsivity, which can make a
person more likely to become alcoholic. Genes may also influence the level
of dopamine in the brain. Researchers have suggested that high dopamine
levels may in turn influence the susceptibility to alcoholism.
