Depression, anxiety and somatization are the most common mental disorders in primary
care as well as medical specialty populations; each is present in at least 5-10% of
patients and frequently comorbid with one another. An efficient means for measuring
and monitoring all three conditions would be desirable.
Evidence regarding the psychometric and pragmatic characteristics of the Patient Health
Questionnaire (PHQ)-9 depression, generalized anxiety disorder (GAD)-7 anxiety and
PHQ-15 somatic symptom scales are synthesized from two sources: (1) four multisite
cross-sectional studies (three conducted in primary care and one in obstetric-gynecology
practices) comprising 9740 patients, and (2) key studies from the literature that
have studied these scales.
The PHQ-9 and its abbreviated eight-item (PHQ-8) and two-item (PHQ-2) versions have
good sensitivity and specificity for detecting depressive disorders. Likewise, the
GAD-7 and its abbreviated two-item (GAD-2) version have good operating characteristics
for detecting generalized anxiety, panic, social anxiety and post-traumatic stress
disorder. The optimal cutpoint is > or = 10 on the parent scales (PHQ-9 and GAD-7)
and > or = 3 on the ultra-brief versions (PHQ-2 and GAD-2). The PHQ-15 is equal or
superior to other brief measures for assessing somatic symptoms and screening for
somatoform disorders. Cutpoints of 5, 10 and 15 represent mild, moderate and severe
symptom levels on all three scales. Sensitivity to change is well-established for
the PHQ-9 and emerging albeit not yet definitive for the GAD-7 and PHQ-15.
The PHQ-9, GAD-7 and PHQ-15 are brief well-validated measures for detecting and monitoring
depression, anxiety and somatization.
Copyright 2010. Published by Elsevier Inc.