1965, 1966) as a challenge. Consequently, the sig-
nificance of Eysenck’s work lies less in the validity
of his conclusions (which many deemed flawed)
than in the attack he made on the field’s
complacency.
As mentioned earlier in this chapter, the evi-
dence concerning the efficacy of psychotherapy is
now considerably more favorable. Still, an under-
current of suspicion remains (Dawes, 1994). To
better understand the nature of therapeutic change,
we consider issues of research design and method,
the results of outcome studies, and the process of
change itself.
Issues in Psychotherapy Research
It is not enough to collect 25 patients undergoing
psychoanalytic therapy, administer before-and-after
measures of adjustment, determine that positive
changes have occurred after 6 months, and then
conclude that psychoanalytic treatment is effective.
Would a comparable group of patients without
therapy have shown improvement? Would a similar
group undergoing systematic desensitization have
improved as much? Was the improvement due to
the psychoanalytic procedures employed, or was
the crucial factor the mere presence of a warm,
interested person who listened? The simple design
suggested in our example does not permit answer-
ing any of these important questions.
As with many psychological experiments (see
Chapter 4), studies that seek to investigate the efficacy
of psychotherapy typically employ an experimental
group and a control group of patients. The experi-
mental group, ortreatment group, receives the treat-
ment being investigated, whereas thecontrol group
does not. Control groups can take many forms. In a
waiting list control group, patients’treatment is delayedBOX11-5 Focus on Professional Issues: Eysenck’s BombshellIn arriving at his conclusions about the efficacy of psy-
chotherapy, Eysenck considered statistical outcome
data from over 7,000 patients. These patients included
five psychoanalytic groups and fourteen groups who
had undergone“eclectic”therapy. As control data,
Eysenck employed the discharge rate among hospital-
ized patients from New York State hospitals and the
amount of improvement that occurred in individuals
who were seeking insurance settlements and were
receiving medical treatment from general
practitioners.
Basically, Eysenck claimed that 72% of the
patients who had received only custodial or medical
care had improved, whereas only 44% of the patients
who had received psychoanalytic treatment and only
66% of the patients who had received eclectic therapy
showed improvement. Clearly, a smaller percentage of
psychotherapy patients than control patients showed
improvement.
While some have argued for the validity of
Eysenck’s conclusions (e.g., Rachman, 1973; Truax &
Carkhuff, 1967), others have vehemently disagreed
(e.g., Bergin, 1971; deCharms, Levy, & Wertheimer,
1954). The criticisms have centered on Eysenck’s failure
to match participants in the treatment and controlgroups. In fact, there really was no control group in the
classic sense, and there certainly was no matching for
education, social class, personality structure, expecta-
tions about therapy, and so on. Also, there was little
evidence that physicians and psychiatrists were using
the same standards for improvement. Finally, there is a
question about how Eysenck calculated his improve-
ment rates. For example, Bergin (1971) argued that the
improvement rate of custodial and medical care groups
was really 30% rather than 72% as calculated by
Eysenck.Hans EysenckANNA WIDOFF Agence France Presse/Newscom334 CHAPTER 11