This page is for general education and is not medical advice. It is not a substitute for diagnosis or treatment by a qualified professional. If this is an emergency, call 911 or 988.
Depression is diagnosed clinically — through a conversation with a qualified professional, not with a lab test or brain scan. A clinician asks about your symptoms, how long they’ve lasted, and how much they affect your life, often using a brief standardized questionnaire, and rules out other medical causes. The good news is that an evaluation is usually straightforward, and it opens the door to treatment that works.
Key facts
- There is no single lab test for depression; diagnosis is based on a clinical evaluation (NIMH, MedlinePlus).
- Clinicians look for core symptoms present most of the day, nearly every day, for at least two weeks (NIMH).
- Screening questionnaires (such as the PHQ-9) help measure symptom severity and track progress (APA).
- Part of diagnosis is ruling out medical contributors, like thyroid problems (MedlinePlus).
What the evaluation involves
- A discussion of symptoms — mood, interest, sleep, appetite, energy, concentration, guilt, and any thoughts of self-harm.
- Duration and impact — how long symptoms have lasted and how they affect work, relationships, and daily life.
- A standardized screening tool to gauge severity and provide a baseline.
- A medical review to rule out other causes and check for conditions or medications that can mimic or worsen depression.
- A history of any high-energy or elevated periods, which helps distinguish depression from bipolar disorder.
Who can diagnose depression
Primary care providers, psychiatrists, psychologists, and other licensed mental health professionals can evaluate and diagnose depression. Many people start with their primary care provider.
How to prepare
- Note when symptoms started and what makes them better or worse.
- List medications and other health conditions.
- Be honest about alcohol, substances, and any thoughts of self-harm — clinicians ask so they can help, not judge.
A self-check can help you organize your thoughts before an appointment, but it is not a diagnosis — only a professional can diagnose depression.
From our clinical review. People sometimes worry the evaluation will be intimidating or that they’ll be “labeled.” In practice it’s mostly a conversation, and a diagnosis is just a useful shorthand that points to treatments known to help. Putting a name to what you’ve been carrying is often a relief, not a burden.
If you think you might be depressed, the next step is help. Explore depression treatment options or take a private, two-minute depression self-check to prepare.
Frequently asked questions
How is depression diagnosed?
A clinician diagnoses depression through a clinical interview about your symptoms, their duration, and their impact, often supported by a standardized screening questionnaire — while ruling out medical causes. There is no single lab test for depression.
Is there a test for depression?
There is no blood test or scan that diagnoses depression. Clinicians may use validated questionnaires (such as the PHQ-9) to measure symptoms, and may order lab tests to rule out conditions like thyroid problems, but the diagnosis is made clinically.
What should I expect at a depression evaluation?
Expect questions about your mood, sleep, appetite, energy, concentration, and any thoughts of self-harm, plus how long symptoms have lasted and how they affect daily life. The clinician may also ask about your medical history and any past high-energy periods.
Sources
- Depression — National Institute of Mental Health (NIMH)
- Depression — MedlinePlus, U.S. National Library of Medicine
- Depression — American Psychological Association (APA)
Reviewed against the sources above. This page is educational and is not medical advice.