Researching Abnormality 163
using data collected from the same participants at multiple points in time.
Specifi cally, such studies track a group of children or adults over time and ob-
serve whether a disorder develops. The presence or absence of the disorder is
then correlated with a neurological factor (perhaps information about brain
structure or function or hormone levels), a psychological factor (cognitive or
emotional functioning, beliefs, or personality traits), or a social factor (family
and other intimate relations, school performance, or socioeconomic status)
that typically was assessed at an earlier point in time. Factors that are signifi -
cantly correlated with the subsequent emergence of the disorder are taken to
signal risk for developing that disorder. However, because such longitudinal
studies are usually correlational, researchers cannot infer causality on the ba-
sis of the fi ndings. As with virtually all correlational studies, many factors can
explain differences observed in longitudinal studies.
Case Studies
Research on psychopathology may also rely on case studies, which focus in detail on
one individual and the factors that underlie that person’s psychological disorder or dis-
orders. For instance, someone noticed that a patient had a very bad sore throat prior
to developing symptoms of obsessive-compulsive disorder (OCD)—a disorder that is
characterized by frequent and intrusive unwanted thoughts and behaviors that the in-
dividual feels compelled to engage in (we will say more about this in Chapter 7). Stud-
ies that were inspired by this observation found that OCD may sometimes develop
from a particular type of streptococcal infection (Swedo et al., 1998), and eventually
researchers identifi ed pediatric autoimmune neuropsychiatric disorder associated with
streptococcal infection(PANDAS; Giulino et al., 2002). PANDAS appears to arise,
at least in part, when antibodies that attack the strep bacteria also attack the brain’s
basal ganglia. Antibiotics that treat the strep infection (leading to lower levels of an-
tibodies) end up decreasing the OCD symptoms. The discovery of PANDAS began
from a case study. However, additional crucial information could only be revealed
by group studies. For example, parents and siblings of those who develop PANDAS-
related OCD have a higher rate of OCD than does the general population (Lougee
et al., 2000), which suggests that a person’s neurological vulnerability affects whether
he or she will develop the disorder when infected by this type of strep.
Case studies can alert clinicians to possible factors that may exacerbate symp-toms of a particular disorder. Case 5.1 is about such a problem affecting a young
woman with autism—a disorder that is diagnosed in childhood and involves signifi -
cant problems with communication and social interactions (we’ll discuss this disor-
der in more detail in Chapter 14).
Risk factors are usually variables that are asso-
ciated—correlated—with the later emergence of
psychological disorders. For instance, soldiers
who fought in the Gulf War in 1991 were more
likely to develop psychological disorders in the
next year than were soldiers deployed elsewhere
during that time period (Fiedler et al., 2006).
However, the presence of risk factors doesn’t
guarantee that a disorder will develop.AP Photo/Peter Dejong, PoolCASE 5.1 • FROM THE OUTSIDE: Menstruation-Related Exacerbation
of Autism SymptomsA 19-year-old nonverbal girl fulfi lling DSM-IV criteria for autism and severe mental retardation was
referred for aggression and SIB [self-injurious behavior]. At onset of menarche at age 12, agitation
dramatically increased. Her mother recorded cyclical behavioral changes along with her menses.
Before each menses, she became withdrawn, apathetic, quiet, irritable, and easily agitated with
increased tantrums and appeared anxious. She also had a cyclical amplifi cation of baseline au-
tistic behaviors: stereotypies (rocking), sensitivity to changes, and sensitivity to noise. New-on-
set cyclical hand-biting was so intense that scarring resulted, and cyclical aggression directed at
objects and others occurred several times daily. Teacher reports recorded and corroborated ag-
gression and SIB that corresponded to the days before the onset of her menstrual period. Within 1
day of menstrual onset, mood symptoms and SIB abated. Neither behavioral therapy with positive
or negative reinforcement nor treatment with acetaminophen or ibuprofen yielded improvement.
Treatment with paroxetine [Paxil, an SSRI medication] 20 mg every morning resulted in improve-
ment of premenstrual mood symptoms and premenstrual exacerbated SIB. On discontinuation of
paroxetine on two distinct occasions, cyclical mood symptoms, aggression, and SIB returned.
(Lee, 2004, p. 1193)Case studies (in studies of psychopathology)
A research method that focuses in detail on
one individual and the factors that underlie
that person’s psychological disorder or
disorders.