408 CHAPTER 9
isn’t consuming alcohol, he or she may experience symptoms related to opioid with-
drawal, which are unpleasant. This experience in turn may induce the person to con-
sume more alcohol to produce more opioids (Gianoulakis, 2001). In other words, with
chronic use, drinking more alcohol may become negatively reinforcing—it removes an
unpleasant state.
Biological By-products of Alcoholism People who frequently
drink a lot of alcohol may become malnourished when
the calories in alcohol substitute for calories from food
(Mehta et al., 2006). Such malnourishment can include a
defi ciency in vitamin B1, which eventually causes several
key parts of the brain to atrophy—including the mamillary
bodies and the thalamus. Because these brain structures are
important for storing new information in memory, drink-
ing a lot of alcohol can indirectly lead to chronic memory
problems (which produces a condition called Korsakoff’s
syndrome). Figure 9.9 shows a result of such brain atro-
phy: the increased size of the fl uid-fi lled hollow areas, the
ventricles, in the center of the brain.
Frequent high levels of alcohol use can also adversely
affect the liver, which fi lters impurities from the blood; when a person drinks too
much alcohol for too long a period of time, the liver develops scar tissue, which
affects its ability to function. This condition is known as cirrhosisof the liver; it is
potentially lethal and more likely to occur when malnutrition is present along with
alcohol abuse or dependence (Lieber, 2003).Why We Get HangoversA hangover occurs the day after a person has been intoxicated
by alcohol, and consists of a bad headache, nausea, and perhaps feeling dizzy and
disoriented. These symptoms arise in part because alcohol is dehydrating: Alcohol is,
essentially, a toxin, and the kidneys use water to remove toxins in the blood. Thus,
the more alcohol a person drinks, the more water the kidneys use in the process of
clearing out this toxin. But becoming dehydrated is only part of the reason we get
hangovers. While the kidneys are working to remove the toxin, so is the liver. The
liver relies on a two-step process to break down alcohol. First, the liver converts
alcohol into a substance called acetaldehyde (a chemical that is related to formalde-
hyde), which is another toxin; second, it converts acetaldehyde to acetate, which is
harmless. However, some people’s livers cannot effectively carry out the second step,
leaving their bodies subject to a toxin produced by their own livers!
If a person has become alcohol dependent, he or she may discover that one way
to reduce the symptoms of a hangover is to drink more alcohol. For people with
alcohol dependence, a hangover is more than simply being dehydrated or even hav-
ing excess levels of acetaldehyde. It is also an indication that their bodies are going
through alcohol withdrawal as the alcohol leaves the system (Cicero, 1978); drink-
ing more alcohol can temporarily diminish the discomfort of the withdrawal symp-
toms. For a heavy drinker, withdrawal symptoms include headaches, weakness,
tremors, anxiety, higher blood pressure, seizures, and increased heart and breathing
rates. An extremely heavy drinker can also experience fever, agitation and irritabil-
ity, as well as more severe symptoms such as confusion, convulsions, and vi-
sual hallucinations. All these alcohol withdrawal symptoms are collectively referred
to as delirium tremens, or “the DTs.” Such withdrawal symptoms normally begin
within 4 days after the person last drank alcohol (Romach & Sellers, 1991). De-
lirium tremens can be potentially lethal; thus, when people with alcohol dependence
are ready to stop drinking, they should have a physician supervise the process.Genetics of Alcoholism
The tendency to abuse drugs is affected by genes. One sign of this is the fact that
substance abuse disorders tend to run in families. However, only the genetics of al-
coholism has been studied in depth. So, we will restrict our discussion of the genet-
ics of depressant abuse and dependence to this single (very important) substance.9.9 • Alcohol Abuse and
Dependence: Effects on the
Brain One of the effects of long-term
alcohol dependence—alcoholism—is
enlarged ventricles (the cavities in the
brain fi lled with cerebrospinal fl uid)
(Rosenbloom, Sullivan, & Pfefferbaum,
2003). (a) The ventricles in this MRI
scan are normal size; (b) the enlarged
ventricles in this MRI scan are those of
a man with alcohol dependence. The
enlargement of the ventricles refl ects the
reduced size of a number of brain areas.
These neurological changes may explain
some of the memory problems associated
with alcohol dependence.
Source: Rosenbloom, M., Sullivan, E.V., and
Pfefferbaum, A. Using magnetic resonance
imaging and diffusion tensor imaging to assess
brain damage in alcoholics. Alcohol Research &
Health 27(2):146–152, 2003.Figure 9.9g99(a) (b)Delirium tremens (DTs)
The symptoms of alcohol withdrawal
marked by confusion, convulsions, visual
hallucinations, and fever.