Utility and limitations of PHQ-9 in a clinic specializing in psychiatric care

Abstract

BackgroundThe Patient Health Questionnaire-9 (PHQ-9), despite its excellent reliability and validity in primary care, has not been examined for administration to psychiatric patients. This study assesses the accuracy of PHQ-9 in screening for major depressive episode and in diagnosing major depressive episode in patients of a psychiatric specialty clinic.MethodsWe compared operational characteristics of PHQ-9 as a screening and diagnostic instrument to DSM-IV-TR diagnosis by a trained psychiatrist as a reference standard. The reference criteria were “current major depressive episode” or “current major depressive episode with major depressive disorder”. PHQ-9 was used with two thresholds: diagnostic algorithm and summary scores (PHQ-9 ≥ 10). The optimal cut-off points of PHQ-9 summary scores were analyzed using a receiver operational characteristics (ROC) curve.ResultsFor “current major depressive episode”, PHQ-9 showed high sensitivity and high negative predictive value at both thresholds, but its specificity and positive predictive value were low. For “current major depressive episode with major depressive disorder”, PHQ-9 also showed high sensitivity and high negative predictive value at both thresholds, but the positive predictive value decreased more than that for “current major depressive episode”. The ROC analysis showed the optimal cut-off score of 13/14 for “current major depressive episode”.ConclusionsPHQ-9 is useful for screening, but not for diagnosis of “current major depressive episode” in a psychiatric specialty clinic.

Validity of the Patient Health Questionnaire-9 for DSM-IV major depressive disorder in a sample of Canadian working population

“…High specificity (490%) was reached with a threshold of 10 or higher, but a high positive predictive value was not reached with any cut-off score. The salient implication is that PHQ-9 used in psychiatric specialties might be suitable for screening purposes with the threshold of 10 for MDD, but not for diagnostic purposes (Inoue et al, 2012). Previous studies in India, China and South Korea have shown that the sensitivity and specificity of the PHQ-9 ranged from 0.80 to 0.93, and from 0.75 to 0.86, respectively, at the cutoff point of 5 (Wang et al, 2014;Han et al, 2008;Poongothai et al, 2009).…”

Long-term evolution of patient-reported outcome measures in spinocerebellar ataxias

“…[5] PHQ-9 is a brief self-rating questionnaire that is known for its excellent feasibility, reliability, validity and sensitivity but lower specificity and positive predictive value. [21][22][23] Overall it has been shown to be a valid measure of depression in different cultures and translations. [24] The use of PHQ-9 in ataxia patients is complicated by the fact that one of the 9 items is related to slowness of movements and speech which may be due to ataxia rather than reflecting depressive mood.…”

Prevalence of depressive symptoms and its predicted factors among medical students in University of Bisha, Saudi Arabia

“…Therefore, major depressive was accounted for if the answer to item number 1 or 2 and four or more of the remaining PHQ-9 items recorded at least as "more than half the days". Based on these criteria, a PHQ-9 score of ≥10 was used as a diagnostic cutoff point for depressive symptoms as previously recommended in the literature [17,18].…”