The aim of this study was to determine the reliability and validity of a Chinese version of the Patient Health Questionnaire–9 item (PHQ-9) and its 2 subscales (1 item and 2 items) for the screening of major depressive disorder (MDD) among adolescents in Taiwan.
A total of 2257 adolescents were recruited from high schools in Taipei. The participants completed assessments including demographic information, the Chinese version of the PHQ-9, and the Rosenberg Self-Esteem Scale, and data on the number of physical illnesses and mental health service utilizations were recorded. Among them, 430 were retested using the PHQ-9 within 2 weeks. Child psychiatrists interviewed a subsample of the adolescents (n = 165) using the Kiddie-Schedule for Affective Disorder and Schizophrenia Epidemiological Version as the criterion standard.
The PHQ-9 had good internal consistency (α = 0.84) and acceptable test–retest reliability (0.80). The participants with higher PHQ-9 scores were more likely to have MDD. Principal component factor analysis of the PHQ-9 yielded a 1-factor structure, which accounted for 45.3% of the variance. A PHQ-9 score ≥15 had a sensitivity of 0.72 and a specificity of 0.95 for recognizing MDD. The area under the receiver operating characteristic curve was 0.90. The screening accuracy of the 2 subscales was also satisfactory, with a Patient Health Questionnaire–2 item cutoff of ≥3 being 94.4% sensitive and 82.5% specific and a Patient Health Questionnaire–1 item cutoff of ≥2 being 61.1% sensitive and 87.7% specific.
The PHQ-9 and its 2 subscales appear to be reliable and valid for detecting MDD among ethnic Chinese adolescents in Taiwan.
Tsai et al (1) reported the validity of the Patient Health Questionnaire-9 items (PHQ-9) and its 2 subscales (PHQ-2 items and PHQ-1 item) for Chinese adolescents with depression by targeting Kiddie-Schedule for Affective Disorder and Schizophrenia Epidemiological Version as the criterion standard. They concluded that PHQ-9 and its 2 subscales can be used for the screening Chinese adolescents with major depressive disorder (MDD). I have some concerns about their study.
The first concern is the best cutoff point for the screening of MDD by PHQ-9. Richardson et al (2) reported that 11/10 is recommended to differentiate MDD with a sensitivity of 89.5% and a specificity of 77.5%, which is based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), as the criterion standard. On this point, Ganguly et al (3) reported the validity of PHQ-9 for Indian adolescents, presenting 5/4 as the ideal cutoff for screening with a sensitivity of 87.1% and a specificity of 79.7%. But the criterion standard for depression was the International Classification of Diseases, 10th Revision in their study. I suppose that the discrepancy of the cutoff point among American, Chinese and Indian adolescents may be related to the selection of criterion standard, and the same criterion standard for MDD is recommended for checking ethnic differences of MDD by PHQ-9.
Second, Tsai et al did not compare the difference among each area under the curve (AUC) of PHQ-9, PHQ-2 and PHQ-1 by receiver operating characteristic (ROC) curve analysis in their Figure 2. As SPSS software does not prepare for the statistical command of comparing each AUC, the authors only presented 0.90, 0.87 and 0.81 as AUCs of PHQ-9, PHQ-2 and PHQ -1. Richardson et al (2, 4) reported that the sensitivity of the PHQ-2 is lower than that of the PHQ-9 for American adolescents by selecting best cutoff point, and I recommend Tsai et al the additional analysis for checking the superiority among three indicators from PHQ.
Allgaier et al (5) reported the screening ability of PHQ-9 by using DSM-IV as the main criterion standard. They presented two procedures for PHQ-9 screening such as "the categorical scoring procedure" and "the dimensional scoring procedure". The "categorical scoring procedure" was conducted according to the algorithms for clinical diagnosis based on DSM- IV criteria. In contrast, the "dimensional scoring procedure" utilized appropriate cutoff points, and Allgaier et al (5) concluded that there was an advantage of "dimensional scoring procedure" for PHQ-9 screening for detecting depression. On this point, Tsai et al (1) adopted the "dimensional scoring procedure" for the screening of MDD by PHQ-9. PHQ-2, one of the short versions of the PHQ-9, is composed of two core items such as the lack of pleasure and depressed mood, which is indispensable for the diagnosis of MDD. As a final concern, I recommend presenting screening ability of PHQ-9 by "categorical scoring procedure".
My three suggestions would lead to add information on the characteristics of PHQ-9 and its subscales.
References
1. Tsai FJ, Huang YH, Liu HC, Huang KY, Huang YH, Liu SI. Patient health questionnaire for school-based depression screening among Chinese adolescents. Pediatrics. 2014;133(2):e402-409
2. Richardson LP, McCauley E, Grossman DC, et al. Evaluation of the Patient Health Questionnaire-9 Item for detecting major depression among adolescents. Pediatrics. 2010;126(6):1117-1123
3. Ganguly S1, Samanta M, Roy P, Chatterjee S, Kaplan DW, Basu B. Patient health questionnaire-9 as an effective tool for screening of depression among Indian adolescents. J Adolesc Health. 2013;52(5):546-551
4. Richardson LP, Rockhill C, Russo JE, et al. Evaluation of the PHQ- 2 as a brief screen for detecting major depression among adolescents. Pediatrics. 2010;125(5):e1097-1103
5. Allgaier AK, Pietsch K, Fruhe B, Sigl-Glockner J, Schulte-Korne G. Screening for depression in adolescents: validity of the patient health questionnaire in pediatric care. Depress Anxiety. 2012;29(10):906-913
Conflict of Interest:
None declared