FORMULA
Addition of the selected points.
FACTS & FIGURES
The PHQ-9 is a validated, 9-question tool to assess for the
degree of
depression
present in an individual; the last question is not scored, but
is useful
functionally to help the clinician assess the impact of the
patient's
symptoms on
his or her life.
EVIDENCE APPRAISAL
The PHQ-9 was initially developed by Kroenke et al (2001), as a
subset
of 9
questions from the full PHQ, which had previously been derived
and
studied in a
cohort of 6,000 patients in 8 primary care clinics and 7
obstetrics-gynecology
clinics (Spitzer 1999). PHQ-9 scores ≥10 were found to be 88%
sensitive
and also 88%
specific for detecting MDD. Criterion validity was also assessed
in a
sample of 580
patients.
The PHQ-9 has also been validated in several additional
subpopulations,
including in
psychiatric patients (Beard 2016), patients with medical
comorbidities
such as
multiple sclerosis (Ferrando 2007) and Parkinson’s disease
(Chagas
2013), pregnant
patients (Sidebottom 2012), and in an occupational health
setting
(Volker 2016).
A meta-analysis of 29 studies including 6,725 patients found
similar
sensitivity
(88%, 95% CI 83-92%) and specificity (85%, 95% CI 82-88%) for a
cutoff
of ≥10 as did
the previous studies, both overall and for subgroups. Notably,
they
found that when
used in the primary care setting, only approximately 50% of
patients
screening
positive on the PHQ-9 in fact had major depression (Levis 2019).