Differential response to placebo among patients with social phobia, panic disorder, and obsessive-compulsive disorder.
OBJECTIVE
Placebo effects in treatment of three anxiety disorders were compared.


METHODS
Treatment response and patients' treatment expectancy were examined by using data from 70 patients with obsessive-compulsive disorder, social phobia, or panic disorder who received placebo in three randomized, controlled trials comparing cognitive behavior therapy, medication, and their combination to placebo.


RESULTS
Patients with obsessive-compulsive disorder were less likely to respond to placebo than patients with generalized social phobia or panic disorder. Differential expectancy did not account for these findings.


CONCLUSIONS
Further examination of the placebo effect across the anxiety disorders may elucidate maintenance mechanisms of these disorders and have implications for development of more effective treatments.
Huppert
Jonathan D
JD
Center for Treatment and Study of Anxiety, University of Pennsylvania School of Medicine, 6th Floor, 3535 Market St., Philadelphia, PA 19104, USA. huppert@mail.med.upenn.edu
Schultz
Luke T
LT
Foa
Edna B
EB
Barlow
David H
DH
Davidson
Jonathan R T
JR
Gorman
Jack M
JM
Shear
M Katherine
MK
Simpson
H Blair
HB
Woods
Scott W
SW
D000328:Adult; D001294:Attitude to Health; D015928:Cognitive Behavioral Therapy; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D016584:Panic Disorder / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D010698:Phobic Disorders / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D015990:Placebo Effect; D010919:Placebos / Q000627:therapeutic use; D011569:Psychiatric Status Rating Scales; D011619:Psychotropic Drugs / Q000627:therapeutic use; D012720:Severity of Illness Index; D016896:Treatment Outcome
D010919:Placebos; D011619:Psychotropic Drugs