BACKGROUND: Japanese family physicians have limited psychiatric training, see a large volume of patients, and would benefit from the use of a mental-health screening tool. This study was an initial investigation into the feasibility and validity of using the Patient Health Questionnaire (PHQ) in the primary care setting in Japan.
METHODS: Feasibility was determined by surveying 149 patients from three primary care practices. Of this sample, a Japanese psychiatrist interviewed 98 participants to assess the validity of the PHQ. Based on the psychiatrist's results, sensitivity, specificity, positive predictive value, kappa statistic and the Likelihood Ratio were examined.
RESULTS: Some 83% of patients reported being “comfortable” in filling out the PHQ. Physicians (82%) reported that the information provided was “valuable” in understanding and treating the patient. The sensitivity of the PHQ in detecting any mental diagnosis was 93%, specificity was 81%, and the positive predictive value was 47%. In subjects with mood disorders, sensitivity was 75%, specificity was 88%, and the positive predictive value was 47%. The kappa reliability coefficients between the PHQ and psychiatrist diagnoses were 0.53 for any mental disorder and 0.51 for any mood disorder. In the case of any mental disorder, the Likelihood Ratio of a positive test (LR+) for the PHQ was 4.8. In the case of any mood disorder, the LR+ for the PHQ was 6.5.
CONCLUSIONS: The Japanese version of the PHQ was useful for detecting mental and mood disorders.