The PHQ-15: validity of a new measure for evaluating the severity of somatic symptoms.
OBJECTIVE
Somatization is prevalent in primary care and is associated with substantial functional impairment and healthcare utilization. However, instruments for identifying and monitoring somatic symptoms are few in number and not widely used. Therefore, we examined the validity of a brief measure of the severity of somatic symptoms.


METHODS
The Patient Health Questionnaire (PHQ) is a self-administered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-15 comprises 15 somatic symptoms from the PHQ, each symptom scored from 0 ("not bothered at all") to 2 ("bothered a lot"). The PHQ-15 was administered to 6000 patients in eight general internal medicine and family practice clinics and seven obstetrics-gynecology clinics. Outcomes included functional status as assessed by the 20-item Short-Form General Health Survey (SF-20), self-reported sick days and clinic visits, and symptom-related difficulty.


RESULTS
As PHQ-15 somatic symptom severity increased, there was a substantial stepwise decrement in functional status on all six SF-20 subscales. Also, symptom-related difficulty, sick days, and healthcare utilization increased. PHQ-15 scores of 5, 10, 15, represented cutoff points for low, medium, and high somatic symptom severity, respectively. Somatic and depressive symptom severity had differential effects on outcomes. Results were similar in the primary care and obstetrics-gynecology samples.


CONCLUSIONS
The PHQ-15 is a brief, self-administered questionnaire that may be useful in screening for somatization and in monitoring somatic symptom severity in clinical practice and research.
Kroenke
Kurt
K
Regenstrief Institute for Health Care, Department of Medicine, Indiana University, RG-6 1050 Wishard Blvd., Indianapolis, IN 46202, USA. Kkroenke@regenstrief.org
Spitzer
Robert L
RL
Williams
Janet B W
JB
D000328:Adult; D000368:Aged; D003863:Depression / Q000175:diagnosis / Q000523:psychology; D003937:Diagnosis, Differential; D005194:Family Practice; D005260:Female; D006801:Humans; D007388:Internal Medicine; D008297:Male; D008875:Middle Aged; D010348:Patient Care Team; D010555:Personality Inventory / Q000706:statistics & numerical data*; D011247:Pregnancy; D011594:Psychometrics; D015203:Reproducibility of Results; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000523:psychology