title: The 6-item Kessler psychological distress scale to survey serious mental illness among Chinese undergraduates: Psychometric properties and prevalence estimate.
abstract: OBJECTIVE
  To evaluate the psychometric properties of the 6-item Kessler psychological distress scale (K6) in screening for serious mental illness (SMI) among undergraduates in a major comprehensive university in China.
  
  
  METHODS
  The K6 was self-completed by 8289 randomly sampled participants. A group of them (n=222) were re-assessed using K6 and interviewed using the Chinese version of Composite International Diagnostic Interview 3.1 (CIDI-3.1).
  
  
  RESULTS
  The test-retest reliability of the K6 scale was 0.79, the Cronbach's alpha was 0.84, and its area under the receiver operating curve (AUC) for diagnosing CIDI-3.1 SMI was 0.85 (95% CI=0.80-0.90). For the optimal cut-off of K6 (12/13), the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and classification accuracy (AC) were 0.83, 0.79, 0.60, 0.93, and 0.80, respectively. The 12-month prevalence of SMI was estimated as 3.97% using this optimal cut-off. Binary logistic regression analysis (including gender, ethnicity, grade, number of siblings and family residency location) showed that only family residency location in rural areas compared to urban areas was significantly associated with more SMI.
  
  
  CONCLUSIONS
  This study documented the value of using the K6 for detecting SMI in Chinese undergraduate populations and supported its cross-cultural reliability and validity.
authors.affiliation: Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Yu-kun
authors.initials: YK
authors.lastname: Kang
authors.affiliation: Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China; State Key Laboratory of Biotherapy, Psychiatric Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China. Electronic address: guowjcn@163.com.
authors.forename: Wan-jun
authors.initials: WJ
authors.lastname: Guo
authors.affiliation: West China School of Public Health, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.affiliation: West China School of Public Health, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Yue-hui
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Xiao-jing
authors.initials: XJ
authors.lastname: Li
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Zheng-ping
authors.initials: ZP
authors.lastname: Tan
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Ze-Ren
authors.initials: ZR
authors.lastname: Gesang
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Ying-mei
authors.initials: YM
authors.lastname: Wang
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Chang-bo
authors.initials: CB
authors.lastname: Liu
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Feng
authors.affiliation: Mental Health Education Center, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Qiu-jie
authors.initials: QJ
authors.lastname: Xu
authors.affiliation: Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Sing
authors.initials: S
authors.lastname: Lee
authors.affiliation: Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China; State Key Laboratory of Biotherapy, Psychiatric Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China; West China School of Public Health, Sichuan University, Chengdu, Sichuan, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
mesh_terms: D044466:Asian People / Q000208:ethnology* / Q000523:psychology; D002681:China / Q000208:ethnology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D001523:Mental Disorders / Q000175:diagnosis / Q000208:ethnology* / Q000523:psychology; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D013315:Stress, Psychological / Q000175:diagnosis / Q000208:ethnology* / Q000523:psychology; D013334:Students / Q000523:psychology; D011795:Surveys and Questionnaires; D014495:Universities; D055815:Young Adult