Clinical Psychology

whether the addition of bibliotherapy, reading edu-
cational books about psychological conditions, would
improve outcome in patients receiving medication
for depression. The design of the research illustrates
important features of theexperimental method.
The study was carried out in a primary care
clinic with participants ranging in age from 21 to

50. Theexperimental groupcontained 50 participants
    who within the last month had started taking an
    antidepressant medication. In addition to taking
    medication, the experimental group was instructed
    to read a popular self-help book on depression,
    Feeling Good(Burns, 1999). To ensure compliance,
    those in the experimental group were instructed to
    call in once per week to report which chapters of
    the book they finished that week as well as their
    medication compliance. Thecontrol groupconsisted
    of 50 participants who, like the experimental
    group, had started taking antidepressant medication
    within the last month. Unlike the experimental
    group, these participants did not receive a reading
    assignment, but simply called in once a week to
    report medication compliance.
    The two groups were matched initially on several
    variables, including level of depression before
    medication, gender, age, socioeconomic level, and

overall level of emotional and physical distress.

However, their assignment into the bibliotherapy

or medication-only conditions was determined

randomly. The primary measure of interest was the

level of depression reported at baseline, after 1 month

onmedication,2monthsafterstartingmedication(and

following bibliotherapy for the experimental group),

and at 3-month follow-up. Figure 4-4 shows the

findings for self-reports of depression for the two

groups.Ascanbeseen,depressionscoresfor theexper-

imentalgroup wereclearly lower followingthebiblio-

therapy intervention as well as at follow-up. These

results suggest that bibliotherapy may help alleviate

depression above and beyond the effects of antidepres-

sant medication.

This study illustrates several features of a typical

experimental study. Theexperimental hypothesisbib-

liotherapy may be a useful adjunct to antidepressant

medication in primary care settings was developed

both from observation of similar populations and

from prior published research. Anindependent vari-

ableis one that is supposed to be under the control

of the investigator. It is expected to have a causal

effect on participants’behavior, which is referred

to as thedependent variable. In this study, bibliother-

apy was the independent variable, and it was

0

5

10

15

20

25

30

35

40

Baseline One Month Two Months Three Months

Medication Only

Medication + Bibliotherapy

F I G U R E 4-4 Depression scores at baseline, after starting medication
(one month), after intervention (two months), and at follow-up (three months).

RESEARCH METHODS IN CLINICAL PSYCHOLOGY 107