The Patient Health Questionnaire-9 for measuring depressive symptoms among the general population in Hong Kong

• Published in: Comprehensive psychiatry 2012, Vol.53 (1), p.95-102
• Main Authors: Yu, Xiaonan, Tam, Wilson W.S, Wong, Paul T.K, Lam, Tai Hing, Stewart, Sunita M
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adult and adolescent clinical studies; Aged; Asian Americans; Biological and medical sciences; Charitable foundations; Confidence intervals; Depression; Depression - diagnosis; Depressive Disorder - diagnosis; Female; Health Surveys; Hong Kong; Households; Humans; Male; Mass Screening; Medical sciences; Mood disorders; Primary care; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychometrics; Psychopathology. Psychiatry; Public health; Questionnaires; Reproducibility of Results; Sample size; Sensitivity and Specificity; Studies; Surveys and Questionnaires; Validity
• ISSN: 0010-440X; 1532-8384
• DOI: 10.1016/j.comppsych.2010.11.002

Abstract Objectives The Patient Health Questionnaire-9 (PHQ-9) assesses depressive symptoms by self-report, is brief, and was developed to correspond to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition , criteria for major depression. This article presents information regarding its reliability and validity and the distribution of scores in a Chinese community sample in Hong Kong. Methods A total of 6028 participants 15 years or older were recruited using random household sampling. They completed the Chinese version of the PHQ-9, the Happiness Scale, the Chinese Health Questionnaire, and the Short-Form 12-Item Health Survey (SF-12). Information was also gathered on health and health service use. Results Exploratory factor analysis and confirmatory factor analysis supported a single factor with strong loadings for all 9 items. Multiple-group analyses demonstrated that the structure can be generalized across sex and age groups (ie, adolescents, adults, and individuals 65 years or older). The internal consistency of the PHQ-9 was 0.82. The test-retest reliability over a 2-week interval was 0.76. As expected, the total score of the PHQ-9 was significantly associated with the Chinese Health Questionnaire ( r = 0.49) and the Happiness Scale ( r = −0.41). In addition, as expected, the relationship with the physical component subscale of the SF-12 was significantly weaker ( r = −0.27) than for the mental component subscale of the SF-12 ( r = −0.60). Participants with higher scores on the PHQ-9 were more likely to report having been diagnosed with depression by a physician, having chronic illness, using medicine, and using inpatient and outpatient health services. Almost 40% of participants did not report any depressive symptoms (score, 0). Self-reported symptoms at a level that would qualify for a diagnosis of major depressive disorder were provided by 1.7% of the participants. Conclusions Our data support the reliability and validity of the PHQ-9 in assessing depressive symptoms among the general population in Hong Kong. Its validity against diagnostic interview for major depressive disorder and its sensitivity and specificity should be determined in future studies.