Depression tests compared: PHQ-9, PHQ-2, CES-D, K10, WHO-5
CareOps editorial team · · 6 min read
Mental wellness information and service guidance published by CareOps.
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Read our full editorial standards →Search for a ‘depression test’ and you will find a flood of checks with different names and lengths. More important than which one is most accurate is that **each asks about a different time period and looks at something different**. Pick the one that fits your question and the result becomes much easier to read.
At a glance
- To look closely at depression symptoms over the past two weeks, use the PHQ-9. For a first screen in under a minute, the PHQ-2 fits.
- To count how many days in the past week, use the CES-D. To look at overall emotional distress beyond depression, the K10 works well.
- The WHO-5 asks about how well you have been feeling (well-being) rather than symptoms. Higher scores are better.
What kinds of depression self-tests are there?
There are about five commonly used self-tests related to depression. All of them have research behind their reliability and validity, but they differ in the time period they ask about, how many questions they have and what they measure. Check the differences in the table first, then pick the test that fits what you want to know.
| Test | Questions and period | Best for |
|---|---|---|
| PHQ-9 | 9 questions · past 2 weeks | Looking closely at how strong depression symptoms are |
| PHQ-2 | 2 questions · past 2 weeks | A quick first screen in under a minute |
| CES-D | 20 questions · past week | Counting how many days you felt a certain way |
| K10 | 10 questions · past 30 days | Overall distress spanning depression and anxiety |
| WHO-5 | 5 questions · past 2 weeks | How well you have been feeling (well-being) |
How is the PHQ-9 different from the PHQ-2?
The PHQ-9 asks how often you have experienced each of nine depression criteria over the past two weeks, scoring each from 0 to 3. In the original study of 6,000 people (Kroenke et al., 2001), a score of 10 or more identified major depression with 88% sensitivity and 88% specificity, and 5, 10, 15 and 20 marked the start of mild, moderate, moderately severe and severe depression.
Try a self-assessment without signing inDepression screen (PHQ-9)Recent mood, interest and daily changes. Answer the app’s questionnaire and see your result right away.Start the check →The PHQ-2 asks only the first two PHQ-9 questions: low mood and loss of interest. On its 0–6 range, a score of 3 or more identified major depression with 83% sensitivity and 92% specificity (Kroenke et al., 2003). Because it is short, it is used as a first screen; if you score 3 or more on the PHQ-2, the usual next step is the PHQ-9 for a closer look.
When should I use the CES-D?
The CES-D is a 20-question self-report scale Radloff (1977) created for research in the general population. You answer how many days in the past week you noticed changes in areas such as mood, sleep, appetite and enjoyment. The total runs from 0 to 60, and the result screen shows symptoms as worth looking into more closely from 16 points.
Try a self-assessment without signing inLow mood experiences (CES-D)Mood and daily changes over the past week. Answer the app’s questionnaire and see your result right away.Start the check →Because it counts days, it is good at catching uneven stretches where some days are fine and others are hard. Since it only covers one week, though, an unusually hard week can push the score up.
What do the K10 and WHO-5 look at?
The K10 asks about overall psychological distress over the past 30 days in ten questions, not just depression. It was built for a US national health survey (Kessler et al., 2002) and was good at telling apart people in the community who had mental health difficulties. If you are not yet sure whether it is depression or anxiety, starting with the K10 for an overall picture is one option.
The WHO-5 asks from the opposite direction. In five questions it looks at how often good states came up over the past two weeks, such as a bright mood, energy and feeling rested. A review of 213 studies (Topp et al., 2015) found the WHO-5 is used in more than 30 languages and is sensitive and specific as a depression screen. The result screen shows 13 or below out of 25 as low well-being. The WHO-5 is a gentle place to start if heavier questions feel like too much.
How should I read depression test results?
- A result is a starting point, not a diagnosis — the score helps you look at where you are now; whether it is depression is decided together with an interview.
- Look at the time period — the same person can score differently depending on whether a test asks about one week, two weeks or 30 days.
- Track the trend with the same test — repeating the same test every few weeks shows whether things are improving.
- Combine tests — looking at symptoms (PHQ-9) and well-being (WHO-5) together shows what is hard and what is still holding you up.
If you want to know how depression tends to start before testing, read early signs of depression. To look at other concerns as well, see our free psychological tests guide.
When to talk with a professional
If your score comes out moderate or higher, or low mood and loss of interest have lasted more than two weeks and your sleep, eating or daily routine are shaken, consider seeing a doctor or speaking with a mental health professional. Bringing your test results makes it much easier to start the conversation.
You can also start by looking at your results and talking through, one step at a time, what has been weighing on you lately.
Frequently asked questions
- Which depression self-test is the most accurate?
- Rather than one always being the most accurate, the right test depends on your purpose. The PHQ-9 is widely used to look closely at the past two weeks of symptoms, the PHQ-2 for a quick screen and the K10 for overall distress.
- Different depression tests gave me different results.
- That is common. Each test asks about a different period (one week, two weeks, 30 days) and looks at something different (symptoms, days, well-being). Read the differences as clues about which period and which side of things has been hard.
- How often should I take a depression test?
- For tests that ask about two weeks, such as the PHQ-9 or WHO-5, every two weeks to a month is enough. Testing too often lets a day or two of mood sway the score. Watching the trend on the same test helps most.
- My score was low, but I still feel bad.
- Feeling bad is real even when the score is low. There may be difficulties the test does not ask about, such as relationships, work or loneliness. If you keep feeling weighed down, talk with someone close or a professional regardless of the score.
Sources
- Kroenke et al. (2001), The PHQ-9: validity of a brief depression severity measure, Journal of General Internal Medicine
- Kroenke et al. (2003), The Patient Health Questionnaire-2: validity of a two-item depression screener, Medical Care
- Radloff (1977), The CES-D Scale: a self-report depression scale for research in the general population, Applied Psychological Measurement
- Kessler et al. (2002), Short screening scales to monitor population prevalences and trends in non-specific psychological distress, Psychological Medicine
- Topp et al. (2015), The WHO-5 Well-Being Index: a systematic review of the literature, Psychotherapy and Psychosomatics
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