PHQ-9: Patient Health questionnaire 9 for depression severity
The PHQ-9 model consists of 9 questions which enables the physician to measure the severity of depression and monitor it over the course of treatment.

Over the last 2 weeks, how often have you been bothered by any of the following problems? 
Research authors: Kroenke K, Spitzer RL, Williams JBW
Details Formula Study characteristics Files & References
Model author
Model ID
Revision date
MeSH terms
  • Depression
  • Questionnaires
  • Pleasure
  • Health Status
  • Screening
  • Psychological Tests
  • Psychology
  • Model type
    Linear model (Calculation)
    No Formula defined yet
    Condition Formula

    Additional information

    The patient health questionnaire (PHQ) is a self adminstered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores eacht of the 9 S\DSM-IV criteria as "0" (not at all) to "3" (nearly every day). The PHQ-9 was completed by 6000 patients in 8 primary care clinics (3000 patients) and 7 obstetrics gynaecology clinics (3000 patients). Construct validity was assessed using the 20-item short form general health survy, self reported sick days and clinic visits, and symptom related difficulty. Criterion validity was assessed against an independent structured mental health professional (MHP) interviuw in a sample of 580 patients. 

    Study Population

    Total population size: 6000
    Males: {{ model.numberOfMales }}
    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Age, primary care setting 46 17 years
    Age, obstetrics/gynecology group 31 11 years

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Race, primary care setting White 2370
    African American 390
    Hispanic 120
    Marital status, primary care setting Married 1440
    Never marries 690
    Divorced/seperated/widowed 870
    Education, primary care setting College graduate 810
    Partial college 810
    High school graduate only 990
    Less than high school 390
    Medical conditions, primary care setting Hypertension 750
    Arthritis 330
    Diabetes 240
    Pulmonary 210
    Race, obstetrics/gynecology group White 1170
    African American 450
    Hispanic 1170
    Marital status, obstetrics/gynecology group Married 1560
    Never married 990
    Divorced/separated/widowed 870
    Education, obstetrics/gynecology group College graduate 480
    Partial college 750
    High school graduate only 960
    Less than high school 810
    Medical conditions, obstetrics/gynecology group Hypertension 60
    Arthritis 30
    Diabetes 30
    Pulmonary 60
    PHQ-9: Patient Health questionnaire 9 for depression severity
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    Related files

    Supporting Publications

    The PHQ-9 total score contains:

    {{ resultSubheader }}

    {{ model.survival.PITTitle }}

    {{ model.survival.YNETitle }}

    Notes are only visible in the result download and will not be saved by Evidencio

    The PHQ-9 total score contains: Points

    {{ resultSubheader }}
    {{ chart.title }}

    Outcome stratification

    Result interval {{ additionalResult.min }} to {{ additionalResult.max }}

    Conditional information

    Result interpretation

    PHQ-9 score of ≥10 has a sensitivity of 88% and a specificity of 88% in detecting MDD.

    {{ file.classification }}

    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

    Please enter a comment of rating
    Comments are visible to anyone

    Model feedback

    No feedback yet 1 Comment {{ model.comments.length }} Comments
    Not rated | On {{ comment.created_at }} {{ comment.user.username }} a no longer registered author wrote:

    Please sign in to enable Evidencio print features

    In order to use the Evidencio print features, you need to be logged in.
    If you don't have an Evidencio Community Account you can create your free personal account at:

    Printed results - Examples {{ new Date().toLocaleString() }}

    Evidencio Community Account Benefits

    With an Evidencio Community account you can:

    • Create and publish your own prediction models.
    • Share your prediction models with your colleagues, research group, organization or the world.
    • Review and provide feedback on models that have been shared with you.
    • Validate your models and validate models from other users.
    • Find models based on Title, Keyword, Author, Institute, or MeSH classification.
    • Use and save prediction models and their data.
    • Use patient specific protocols and guidelines based on sequential models and decision trees.
    • Stay up-to-date with new models in your field as they are published.
    • Create your own lists of favorite models and topics.
    A personal Evidencio account is free, with no strings attached! Join us and help create clarity, transparency, and efficiency in the creation, validation, and use of medical prediction models.

    Disclaimer: Calculations alone should never dictate patient care, and are no substitute for professional judgement.