Start here: what these tools are
The PHQ-9 and GAD-7 are short, standard questionnaires used across medicine to measure symptoms of depression and anxiety. The PHQ-9 asks about the features of low mood over the past two weeks; the GAD-7 does the same for anxiety. Each produces a simple score that reflects how heavy the symptoms have been.
They are not diagnoses on their own. They are structured ways of asking how you have actually been, which is more reliable than a passing question in a busy appointment and easy to repeat over time.
Why they matter in long COVID
Because post-COVID mood and anxiety symptoms are common and biologically driven, and because they are so often overlooked beneath the physical complaints, a brief structured screen helps ensure they are noticed.1 That matters most for catching serious difficulty that might otherwise go unspoken.
Used well, these tools give the mood side of the illness the same legitimacy as the physical side. A score on a validated questionnaire is harder to wave away than a feeling, which can be the difference between being taken seriously and being told it is just stress.
standard toolswell-founded associationsensitive: screen and support
Tracking change over time
One of the most useful things about these questionnaires is that they can be repeated. Because the mood component of long COVID often eases over the first months, a score taken now and again later can show real movement, which is both informative and, often, encouraging.
Tracking also helps judge treatment. If something is meant to help mood, repeating the screen gives an objective read on whether it is working, rather than relying on the hard-to-recall sense of whether things are better.
Handling the sensitive questions
The PHQ-9 includes a question about thoughts of self-harm, which is there for a protective reason: to make sure serious distress is noticed and met with support. A response that raises such thoughts is a prompt for care and conversation, not a cause for alarm or judgement.
Approached kindly, this is exactly how screening should work, surfacing something difficult so it can be helped rather than left unspoken. If a screen brings such thoughts to the surface for you, the support note above is the right next step.
self-harm item presentsupport, not judgement
What the score does and does not mean
A high score signals that mood or anxiety symptoms are heavy enough to deserve attention; it does not by itself explain why. In long COVID the why is often biological, so a raised score is a reason to look at the inflammatory, autonomic, and sleep drivers as well as to consider mood-specific support.
Equally, a lower score does not mean nothing is wrong elsewhere. These tools measure mood and anxiety specifically, one part of a multi-system illness, and they work best as one instrument among several rather than as a verdict on the whole picture.
How to use them
These questionnaires are freely available and quick, and many people complete them before an appointment. Bringing a completed screen, or asking to be screened, can be a direct way to get the mood side of the illness onto the agenda.
Treat them as a starting point for a conversation rather than an endpoint. Their value is in opening the door to support and in tracking change, which together make the mood symptoms visible, legitimate, and treatable.
What we don't know
Honest about the edges of the evidence. These are open questions, not settled answers.
- How well general mood questionnaires capture the specific shape of post-COVID mood symptoms.
- Whether symptom overlap with the illness inflates or distorts the scores.
- How often routine screening actually changes care in practice.
- Which cutoffs best identify people who need support in this population.
- How to deliver screening at scale without stigma or alarm.
- Whether tracking scores improves outcomes versus usual care.
What this means for you
If your mood or anxiety symptoms keep getting lost beneath the physical ones, a brief PHQ-9 or GAD-7 screen is a simple way to put them on the record and into the conversation. The tools are free and quick, and a documented score is harder to dismiss than a feeling.
Used kindly, they also catch serious difficulty so it can be met with support rather than missed, and repeating them over time can show real, often encouraging, change. If a screen surfaces thoughts of self-harm, treat that as a reason to reach out, the support note above is there for it, not as a cause for alarm.
And treat a high score as an invitation to look wider, not a closed verdict. In long COVID the mood symptoms usually have biological drivers, so a raised screen is a reason to examine sleep, inflammation, and autonomic strain as much as to consider mood-specific support, and to repeat the screen later to see how things move over time.
References
Each reference links to the source on PubMed, PMC, or the publisher.