Patient Health Questionnaire-9 (PHQ-9)

# of studies reporting psychometric properties: 5

Interpretability

MCID: not established for the SCI population, but for a sample of older primary care patients (n = 434, mean age = 71 (7.4) years, all participants enrolled in the Improving Mood-Promoting Access to Collaborative Treatment (IMPACT)):

MCID = 5 points

Reference: Lowe, B., Unutzer, J., et al. (2004). “Monitoring depression treatment outcomes with the patient health questionnaire-9.” Med Care 42(12): 1194-1201.

SEM: not established for the SCI population, but for a sample of older primary care patients (see Lowe et al. 2004 reference above): SEM for change due to treatment and no control of prior depression = 2.44 SEM for the same number of DSM-IV depressive symptoms at both assessments = 1.32

MDC: not established

• Higher scores indicate increased severity of depression.
• A cut-off score of 10 has been reported to indicate major depression.
• Published data for the SCI population is available for comparison (see the Interpretability section of the Study Details sheet).

Reliability

Internal consistency for the overall PHQ-9 scale was reported to be High (Cronbach’s a=0.83-0.89).

[Bombardier et al. 2004, Richardson and Richardson 2008, Graves & Bombardier 2008, Krause et al. 2009]

Validity

• Correlation of the PHQ-9 is:
  • High with the Older Adult Health and Mood Questionnaire (Spearman’s r=0.781)
  • Moderate with major depressive disorder (MDD) (Spearman’s r=0.530)
  • Moderate with the Satisfaction with Life Scale (Spearman’s r=-0.477).
• PHQ-9 scores were inversely and Moderately correlated with subjective health on the SF-1 (Spearman’s r=0.37).
• For a 3-item screening test with a score cutoff of 3, a sensitivity of 0.87 and specificity of 0.93 were reported; with a score cutoff of 4, a sensitivity of 0.82 and a specificity of 0.95 were reported.
• For the total PHQ-9, a cutoff of 11 was determined to have optimal diagnostic accuracy of MDD. At this cutoff, the PHQ-9 detected 100% (sensitivity) of those with a diagnosis of MDD and had a specificity of 84%.

[Bombardier et al. 2004, Bombardier et al. 2012, Richardson and Richardson 2008, Krause et al. 2009]

Responsiveness

No values were reported for the responsiveness of the PHQ-9 for the SCI population.

Floor/ceiling effect

No values were reported for the presence of floor/ceiling effects in the PHQ-9 for the SCI population.

Reviewer

Dr. Vanessa Noonan, Kyle Diab

Date Last Updated

Mar 16, 2017