Assessment Guide  |   May 9, 2023  |   2 minute read

PHQ-9 | Depression

Patient Health Questionnaire 9 (PHQ-9)

Recommended frequency: Every 2 weeks

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Summary

The Patient Health Questionnaire 9 (“PHQ-9”) is a multi-purpose measure used to identify and monitor depression severity. It is a brief, 9-item version of the original PHQ assessment, which measures a variety of mental health challenges in addition to depression, such as anxiety, panic disorder, sleep disorders, and more. The PHQ-9 was co-created by Drs. Robert L. Spitzer, Janet W.B. Williams and Kurt Kroenke in 1999.

About the PHQ-9

The PHQ-9 combines depression diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) with other leading major depressive symptoms. The key diagnostic symptom criteria adapted from the DSM-IV includes:

  • Two typical signs of depression: anhedonia (referring to the inability or reduced ability to experience pleasure) and depressed mood;
  • Cognitions (e.g. guilt/worthlessness and suicidality/thoughts of death); and
  • Physical symptoms (e.g. change in appetite, difficulty sleeping and concentrating, feeling tired/slowed down or restless).

 

Each of the 9 questions rate the frequency of the symptoms, which factors into the severity index.

Clinicians and clinical leaders will often ask about the differences between the PHQ-9 and other depression scales. In comparison to the other commonly used depression scales (BDI, HAD-D, QIDS), the confidence intervals are quite similar, meaning they have all demonstrated reliability, validity, and are responsive to change. The PHQ-9 has a particularly high validity score, such that when PHQ-9 scores were above 10, the measure was shown to have a sensitivity of 88% and a specificity of 88% for Major Depressive Disorder—meaning that a score above 10 was a good indication that a diagnosis of depression would occur. Each of the major depression scales have their differences, although the PHQ-9 and BDI-II in particular tend to measure relatively equal levels of severity and track symptom change in a similar manner. The PHQ-9 is often preferred to other comparable assessments due to its brevity, which makes it easy to integrate into research or practice, and helps promote high completion rates.

Frequently Asked Questions
Can the PHQ-9 be used for diagnosis?

The PHQ-9 is widely used for diagnosing depression and determining the severity of depression a client is experiencing. It’s important to always discuss each item with the client and ensure they understood the questions, and to gather additional insight into their symptoms and experiences, prior to making a diagnosis.

How often should the PHQ-9 be administered?

To best monitor and respond to symptom changes, the recommended frequency for the PHQ-9 is every 2-4 weeks. A brief and consistent frequency allows the assessment to capture client experiences over the two weeks prior to completion, providing an opportunity to get curious about the results with your client. By digging into the symptoms and uncovering potential causes, you can work together to better understand the factors that may influence their symptom changes.

Can the PHQ-9 be used with all ages?

The PHQ-9 is validated for individuals 18 years of age or older. If you’re looking for measures for younger age groups, please refer to the Child Depression & Anxiety (RCADS 25) measure or the Child Depression (CES-DC) measure.

How long does it take to complete the PHQ-9

The PHQ-9 takes approximately 2-5 minutes to administer and can be completed independently by the client or in session with their clinician.

What’s the difference between the PHQ-9 and other assessments that measure depression?

Compared to other commonly used depression scales (eg. BDI, HAD-D, QIDS), the PHQ-9 presents similar confidence intervals, in terms of demonstrated reliability, validity, and responsiveness to change in symptoms and severity. While all major depression scales are different, the PHQ9 and BDI-II are most similar in their ability to measure relatively equal levels of severity and their approach to monitoring symptom change. The PHQ-9 is most often preferred because of its brevity (9 questions vs. 21 questions), which makes it easier for clients to complete and ultimately allows for a more successful integration into practice, especially when clients are assigned multiple assessments as part of their treatment plan. Though brief, the PHQ-9 has a high validity score, such that when PHQ-9 scores were above 10 (moderate-severe), the measure was shown to have a sensitivity of 88% and a specificity of 88% for Major Depressive Disorder—meaning that a score above 10 was a good indication that a diagnosis of depression was appropriate.

What should I do if my client receives a flag for suicidality (i.e. responds ‘Several Days’ or any higher frequency to question 9)?

Any client who responds with ‘Several Day’ or any higher frequency to question 9 requires further assessment to determine their suicidality risk level and inform the appropriate next steps. Recognizing and appropriately responding to suicidal ideation often requires suicide prevention and response training. If you do not feel equipped to asses the risk level of your client, it is a good idea to refer them to someone who is trained to respond to and treat suicidality. The important thing is to ensure your client is safe and work to maintain their trust while still asking the questions necessary to understand their risk and determine the appropriate treatment response.

When interviewed, Kristin Bruns (LCP, and Assistant Professor in the Department of Counseling, School Psychology and Educational Leadership at Youngstown State University) shared that it’s important to first build a strong bond with your client and generate a deep understanding of their situation, prior to intervening. Clients dealing with these thoughts and feelings often need a clinician who will listen and demonstrate empathy, rather than one who will immediately jump into action. When it comes time to ask more questions, it is recommended to choose evidence-based suicide assessments and treatment tools, and continue to get curious with the client on their responses without overwhelming them.

To learn more about assessing and responding to suicide risk, review this article.

How can I practice using the PHQ-9 with client’s in session?

During our 2nd educational panel with the Yale Measurement-Based Care Collaborative, we all participated in an important exercise to illustrate how simple, yet valuable, using MBC in care can be. The ‘PHQ-9 Three-Ways’ exercise is used by the team at Yale to help any service provider feel comfortable with the simple process of exploring MBC data and getting curious about PHQ-9 responses, collaboratively with their clients, to understand the meaning and impact of their results.

The Yale MBC Collaborative shared sample PHQ-9 scores from three different clients, each with slightly different responses. The audience then reviewed the responses and highlighted what stood out to them, what hypotheses they were forming, and what they might ask the client in session to dig deeper into their experience, understand their perspective and inform treatment discussions and decisions.

Get started by watching this clip and try it for for yourself:

Why did my client score low on the PHQ-9 even though they appear to be experiencing significant amounts of depression?

There are times when what is shown in your clients data, does not align with what they share in care or with how it seems like they’ve been doing overall. This is the perfect time to dive into each of the items on the measure and ensure that you and your client are speaking the same language and understanding them correctly. Their understanding of the language of the measure will impact how they respond, so it’s important that they have a strong understanding of what the question is asking and that you, as their provider, have a strong understanding of how they interpret the language. By getting curious together, you can begin to better understand what the questions and language mean to them, and how that might impact your understanding of their experience.

With a fulsome understanding, there is still often a discrepancy between what what your client is telling you verbally and what their results are showing, highlighting this outlines a large part of the impact of Measurement-Based Care integrated into treatment processes. This presents the perfect opportunity to dig a bit deeper and focus a part of your session around that specific item to learn more about their experience in care and mental health challenges. Doing so will help build your client-clinician bond and ensure that your clients voice and experiences are at the heart of the care process and treatment decisions.

How should I administer the PHQ-9 to clients?

The PHQ-9 can be completed in two ways:

  1. Independently by the client, whether this on their own schedule at home (Greenspace offers automatic delivery for completion on desktop or mobile via text or email) or at the office before session (via tablet, kiosk or pen/paper)
  2. Administered verbally by staff before session or in-session. This can be particularly helpful, and sometimes necessary, when working with clients who have difficulty with reading or comprehension.

Research shows that clients can fill out this assessment successfully on their own and most often require no assistance. However, it’s important to discuss each question before or after completion to ensure you have a shared understanding of what the questions are asking. If you choose to administer the assessment verbally, be sure to ask the question exactly as it is written to ensure their response is accurate and results remain evidence-based.

How do I share the purpose of this form with clients, so they understand why they’re filling it out?

It’s important that clients understand the value of this assessment prior to being asked to complete it. Making the process of measurement valuable to clients is the best way to deepen their engagement in treatment and improve therapeutic alliance and clinical outcomes. For inspiration, here is an example of how you might introduce the PHQ-9 to clients:

“Just like you have your blood pressure taken when you go to the doctors, this assessment is the providers way of measuring your mental well-being. The results we get throughout the course of your treatment will be our way of checking in on your progress, so we can better understand what’s working and what might need to change, talk more deeply about your symptoms and experiences and work together to set goals in treatment, so we both know we’re working towards what matters to you.”

Jessica Barber, PhD, explains this process well and shares how she approaches introducing measures to clients in session:

What does the PHQ-9 measure?

The PHQ-9 measures the presence of depression and its severity. The assessment is brief, with only 9-items, making it easy for clients to complete independently or in-session with their therapist. The PHQ-9 is also one of the top measures leveraged on Greenspace.

The PHQ-9 combines depression diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) with other leading major depressive symptoms. The key symptoms of depression measured include:

  • Anhedonia (referring to the inability or reduced ability to experience pleasure) and depressed mood;
  • Cognitions (e.g. guilt/worthlessness and suicidality/thoughts of death); and
  • Physical symptoms (e.g. change in appetite, difficulty sleeping and concentrating, feeling tired/slowed down or restless).

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