Psychology2016

Consciousness 163

most important pathway of neurons in the brain tied to all forms of addiction and may
be involved in the depression that occurs in some mood disorders (Glangetas et al., 2015;
Mahr et al., 2013; Russo & Nestler, 2013). to Learning Objective 14.9.

But not all drugs produce physical dependence, right? For example,

some people say that you can’t get physically dependent on marijuana.

If that’s true, why is it so hard for some people to quit smoking pot?

PSYCHOLOGICAL DEPENDENCE Not all drugs cause physical dependence; some cause
psychological dependence, or the belief that the drug is needed to continue a feeling
of emotional or psychological well-being, which is a very powerful factor in continued
drug use. The body may not need or crave the drug, and people may not experience the
symptoms of physical withdrawal or tolerance, but they will continue to use the drug
because they think they need it. In this case, it is the rewarding properties of using the
drug that cause a dependency to develop. This is an example of positive reinforcement, or
the tendency of a behavior to strengthen when followed by pleasurable consequences.
to Learning Objective 5.5. Negative reinforcement is also at work here, as tak-
ing the drug will lower levels of anxiety.
Although not all drugs produce physical dependence, any drug can become a focus
of psychological dependence. Indeed, because there is no withdrawal to go through or
to recover from, psychological dependencies can last forever. Some people who gave up
smoking marijuana decades ago still say that the craving returns every now and then
(Roffman et al., 1988).
The effect of a particular drug depends on the category to which it belongs and
the particular neurotransmitter the drug affects. to Learning Objective 2.3. In
this current chapter we will describe several of the major drug categories, including
stimulants (drugs that increase the functioning of the nervous system), depressants
(drugs that decrease the functioning of the nervous system), and hallucinogenics (drugs
that alter perceptions and may cause hallucinations).

Stimulants: Up, Up, and Away

4.12 Identify the effects and dangers of using stimulants.

Stimulants are a class of drugs that cause either the sympathetic division or the central
nervous system (or both) to increase levels of functioning, at least temporarily. In simple
terms, stimulants “speed up” the nervous system—the heart may beat faster or the brain
may work faster, for example. Many of these drugs are called “uppers” for this reason.

AMPHETAMINES Amphetamines are stimulants that are synthesized (made) in labo-
ratories rather than being found in nature. Among the amphetamines are drugs like
Benzedrine, Methedrine, and Dexedrine. A related compound, methamphetamine, is
sometimes used to treat attention-deficit/hyperactivity disorder or narcolepsy. “Crystal
meth” is a crystalline form that can be smoked and is used by “recreational” drug users,
people who do not need drugs but instead use them to gain some form of pleasure.
Like other stimulants, amphetamines cause the sympathetic nervous system to
go into overdrive. to Learning Objective 2.5. Some truck drivers use amphet-
amines to stay awake while driving long hours. Stimulants won’t give people any extra
energy, but they will cause people to burn up whatever energy reserves they do have.
They also depress the appetite, which is another function of the sympathetic division.
Many doctors used to prescribe these drugs as diet pills. Today they are only used on a
short-term basis and under strict medical supervision, often in the treatment of attention-
deficit hyperactivity disorder (Safer, 2015). Diet pills sold over the counter usually con-
tain another relatively mild stimulant, caffeine.

One of the dangers of psychoactive

drugs is that they may lead to physical or

psychological dependence.

psychological dependence

the feeling that a drug is needed to

continue a feeling of emotional or psy-

chological well-being.

amphetamines

stimulants that are synthesized

(made) in laboratories rather than

being found in nature.

hallucinogenics

drugs including hallucinogens and

marijuana that produce hallucinations

or increased feelings of relaxation and

intoxication.

depressants

drugs that decrease the functioning of

the nervous system.

stimulants

drugs that increase the functioning of

the nervous system.