164 CHAPTER 5
Uses and Limits of Case Studies
A case study focuses on a particular individual in detail, often describing neurologi-
cal, psychological, and social factors: Such a study often provides information about
a person’s medical and family history, as well as his or her culture and the context of
the problem. Mental health professionals use case studies for a variety of reasons:- to demonstrate some aspect of diagnosis, etiology, or treatment;
- to provide support for (or evidence against) a particular hypothesis or theory; and
- to train other mental health professionals, who are given case studies and must
then propose diagnoses and appropriate treatments.
This book includes numerous case studies so that you can gain a sense of how
psychological disorders affect people’s lives. Case studies with From the Outside in
the title describe an individual with a disorder from a mental health professional’s
point of view. Case studies with From the Inside in the title are fi rst-person ac-
counts, allowing you to get a patient’s point of view on what it is like to have a
disorder or particular symptoms of a disorder.
Mental health clinicians and researchers must resist the temptation to gener-
alize from a single case: Don’t assume that the fi ndings from a case study neces-
sarily can be extended to other similar cases, let alone to the population at large.
Sometimes the fi ndings can be generalized, but sometimes they cannot be; every
individual is unique, and a person’s particular history presents many possible con-
founding factors. In addition, if a case study relies on correlations among variables,
this method—as usual—prevents us from drawing conclusions about causality.Single-Participant Experiments
Case studies are not necessarily limited to describing the values of variables and
relations among them. In some situations, clinicians and researchers can actually
perform experiments with only a single case. For instance, a researcher could treat
someone suspected of having PANDAS-related OCD with antibiotics and determine
whether the OCD symptoms improved. Experiments with only a single case are
calledsingle-participant experiments. Watson and Rayner conducted a single-
participant experiment with Little Albert.
Single-participant experiments may rely on an ABAB design, which is often
used to measure change in target behaviors as the result of some treatment. In many
cases, the baseline condition is the fi rst A, and administration of a treatment (e.g.,
behavior modifi cation, or any other type of treatment) is B. A single participant
receives both conditions: a baseline condition with no treatment (the fi rst phase
A of the ABAB design), and the treatment (phase B of the ABAB design) (Drotar,
2006). The data for the target behavior in the baseline phase (A) are compared to
the data for that behavior in the next phase (B).
In the second A phase, the treatment in phase B is withdrawn, and researchers
can determine whether, or how quickly, the person’s targeted behavior returns to
baseline (for example, withdrawing behavior modifi cation treatment and observing
what happens with extinction). This second A phase addresses the question “Will
any behavior change from the previous phase persist once treatment is withdrawn?”
The treatment is then presented again in the second B phase.
For instance, people with autism (such as the young woman in Case 5.1) have
diffi culty taking another person’s perspective. One method to help them with this
social skill is to tell them stories in which who, what, when, where, and why are
clear—and ample information is given about the different characters’ perspectives
(Gray, 1996). Such stories are read aloud to the patient from a picture book. Re-
sults of previous research with social stories indicate that they can be helpful, but
in most of those studies the stories were part of a comprehensive intervention that
included other treatments such as social skills training (Swaggart et al., 1995).
A single-participant experiment was performed to determine whether social
stories alone could help decrease tantrums in a 5-year-old boy, Gregg, diagnosedSingle-participant experiments
Experiments with only a single participant.