Depression Screening and PHQ-9

HEALTH DESK

Depression is a mood disorder and one of the most widespread and treatable mental health condition¹, affecting around 5% of the global population². Symptoms include persistent feelings of sadness and loss of interest in activities, feelings of guilt or hopelessness, and more³. Although effective interventions are available, up 50% of depression cases may not be diagnosed or treated appropriately or soon enough⁴. Early identification of symptoms is the first step towards successfully dealing with the problem⁵. Depression screening carried out by primary healthcare providers can help ensure quick and accurate diagnoses⁵.

What is mental health screening

Mental health screening is an essential tool involving various methods for evaluating, diagnosing and monitoring the mental well-being of individuals⁶. General practitioners, the patient’s first point of contact, have access to a variety of tools that are immediate and simple to use, such as self-administered tests, which speed up and optimise the diagnostic and therapeutic process⁶.

Assessment tests for depression and anxiety

Among these tests are the Patient Health Questionnaire-9 (PHQ-9) for depression screening and the General Anxiety Disorder-7 assessment tool (GAD-7)⁶. The GAD-7 can also be used when people with depression have symptoms of anxiety and agitation, or with people who have been diagnosed with both disorders, which is not uncommon⁷. A clinical interview to assess the patient’s symptoms and history usually accompanies the test⁸.

How does the PHQ-9 score work?

The Patient Health Questionnaire-9 (PHQ-9) is a standardised scale for screening, diagnosing and monitoring depression and measuring depression severity⁵. It contains nine questions aligned with the diagnostic criteria for major depressive disorder⁵. Answers are scored from 0 (not at all) to 3 (nearly every day) based on the frequency – and therefore the pervasiveness – of symptoms⁹. Patients answer the questions independently in a few minutes⁵.

The PHQ-9 score ranges from 0 to 27¹. A score of up to and including 4 indicates, in almost all cases, no depression; a score of 5 to 9 suggests mild depression, from 10 to 14 moderate depression, from 15 to 19 moderately severe depression, and a score above 20 indicates severe depression¹. Scores of 15 and above are suggestive of major depression¹.

Assessing the results

The results of these tests should always be assessed by a specialist, who will evaluate them in relation to the diagnostic criteria for major depressive disorder or other types of depression (i.e. presence, number, duration and frequency of specific symptoms)¹.

A doctor will also rule out possible physical causes of depression, recent bereavement or a history of manic episodes¹. A manic episode, even if it occurred in the past, points to a diagnosis of bipolar I disorder, which can be present with or without a major depressive episode⁹.

The PHQ-9 score also helps to determine whether pharmacological treatment is needed¹⁰ and in the monitoring of the therapeutic response¹. A prescription for antidepressants may be indicated with a score of 10, depending on the diagnosis made, and is always recommended if a score is above 20¹⁰. Screening is also useful for detecting risk of suicide¹¹.

Benefits of early diagnosis and monitoring

Depression screening can also be proposed by general practitioners, who are in a position to identify patients who are at risk⁶. The sooner a diagnosis is made, the more effective any proposed treatments and/or management strategies can be, including in the long term¹². This is why it is important to see a doctor at the first symptoms, in order to obtain an early diagnosis and the right treatment¹³.

Courtesy Angelini Pharma

References:

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2. World Health Organization (WHO), Depressive disorder (depression)
3. Chand S. P., Arif H., “Depression”. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430847/
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8. National Health Service (NHS, UK), “Mental Health Assessments”, 17 February 2022 PMCID: PMC4927366, https://pmc.ncbi.nlm.nih.gov/articles/PMC4927366/
9. American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR®), American Psychiatric Association Publishing,  Washington, DC, 2022, pp. 140-142
10. Dejesus R. S., Vickers K. S., Melin G. J., Williams M. D. “A system-based approach to depression management in primary care using the Patient Health Questionnaire-9”. Mayo Clin Proc. 2007 Nov;82(11):1395-402. doi: 10.4065/82.11.1395. PMID: 17976360.
11. Rossom R. C., Coleman K. J., Ahmedani B. K., Beck A., Johnson E., Oliver M., Simon G. E. “Suicidal ideation reported on the PHQ9 and risk of suicidal behavior across age groups”. J Affect Disord. 2017 Jun;215:77-84. doi: 10.1016/j.jad.2017.03.037. Epub 2017 Mar 16. PMID: 28319695; PMCID: PMC5412508.
12. Kraus, C., Kadriu, B., Lanzenberger, R. et al., “Prognosis and improved outcomes in major depression: a review”. Transl Psychiatry9, 127 (2019). https://doi.org/10.1038/s41398-019-0460-3
13. National Health Service (NHS, UK), “Overview – Depression in adults”, 5 July 2023