Only a healthcare professional can diagnose depression. Persistent low mood or loss of interest can be a reason to ask for an assessment. So can other changes or growing difficulty with daily life. A screening questionnaire can organize those symptoms, but it cannot tell you on its own whether you have depression.
What depression can look like
Depression is not defined by sadness alone. Some people notice emptiness, irritability, numbness, or a loss of interest before they recognize a low mood. Other changes can involve sleep, appetite, energy, concentration, movement, guilt, or hopelessness. Daily responsibilities may become harder to manage.
Clinicians look at the whole pattern. They ask which symptoms are present, how often they occur, how long they have lasted, and how much they interfere with life. They also consider whether another condition could explain them. The National Institute of Mental Health explains that symptoms must occur most of the day, nearly every day, for a depression diagnosis. They must last at least two weeks, and one must be depressed mood or loss of interest or pleasure.
You do not need to wait until you meet a checklist threshold to ask for help. A few severe symptoms, a sudden change in functioning, or symptoms that keep returning can still deserve attention.
When to get urgent help
Get immediate help if you may act on thoughts of suicide or self-harm, cannot keep yourself safe, or face another life-threatening emergency.
If you need help now. In the US, Call 988 or text 988. Call 911 if you are in immediate danger. Outside the US, contact your local emergency number or find support in your country.
A screening total cannot determine current suicide risk. Tell a healthcare professional directly about thoughts of death or self-harm, even if your total score is low.
What a depression screen can tell you
A screen records how often you experienced a defined set of symptoms during a set period. It can show whether your answers crossed a follow-up threshold. It also gives you concrete information to discuss at an appointment.
A screen cannot determine the cause of your symptoms. Many problems can overlap with depression. These include sleep trouble, thyroid disease, medication effects, substance use, grief, anxiety, trauma, and bipolar disorder. A clinician will ask about your health, medications, recent events, safety, and history before making a diagnosis.
PHQ-2: a brief first step
The PHQ-2 asks about low mood and loss of interest during the previous two weeks. The total runs from 0 to 6. A score of 3 or higher usually leads to a broader depression assessment rather than a diagnosis.
In the original adult study by Kroenke and colleagues (2003), 580 participants received an independent mental health interview. Most people whose PHQ-2 score reached 3 did not have major depressive disorder on that interview. This is why the result supports follow-up rather than a diagnosis. Performance can differ in other populations.
The PHQ-2 does not ask about most depression symptoms, functioning, suicide, or self-harm. A low score does not rule out a problem.
PHQ-9: a broader symptom screen
The PHQ-9 asks about nine depression symptom areas over the previous two weeks. Its total runs from 0 to 27. The published score bands describe increasing symptom severity:
| Score | Symptom band |
|---|---|
| 0-4 | None to minimal |
| 5-9 | Mild |
| 10-14 | Moderate |
| 15-19 | Moderately severe |
| 20-27 | Severe |
In the original adult validation by Kroenke and colleagues (2001), a smaller group received a structured mental health interview. A PHQ-9 score of 10 or higher was a useful follow-up threshold in that group, but accuracy varies by population and interview method. The result supports further assessment; it does not confirm depression or choose a treatment.
The PHQ-9 also includes a question about thoughts of death or self-harm. Any response other than "not at all" needs direct follow-up, regardless of the total. That question is a safety signal, not a complete suicide-risk assessment.
For more detail, read what your PHQ-9 score means.
How to read your result
Start with the individual answers, not just the total. Note which symptoms changed, when they began, and what they are preventing you from doing. A score near a cutoff should not outweigh marked functional change or a safety concern.
Then consider context. Were you acutely ill, grieving, or changing medication? Were you using more alcohol or another substance, sleeping very little, or experiencing unusually high energy or impulsivity? Those details can change what a clinician needs to assess.
Finally, use the result as one piece of information. A primary care professional can review physical causes and medications. A mental health professional can complete a diagnostic assessment. Either can help decide what support fits your needs and preferences.
When to make an appointment
Consider contacting a healthcare professional when:
- symptoms have lasted about two weeks or keep returning;
- work, school, relationships, self-care, or sleep are getting harder;
- you are using alcohol or other substances to cope;
- you have a history of depression, bipolar disorder, or another mental health condition;
- people close to you have noticed a meaningful change; or
- you are worried, even if a screening score is below its usual cutoff.
At the appointment, bring the questionnaire result if it helps. Also describe the timeline, the most disruptive symptoms, current medications and substances, recent health changes, and any safety concerns. Those details are often more useful than the total alone.
Should you repeat the questionnaire?
There is no universal schedule for repeating a depression screen. Repeat it when the result will answer a clear question and someone will review what changed. Keep the same recall period and answer based on the stated timeframe.
A lower score does not prove that a particular action caused improvement. A higher score does not prove that a condition has worsened. Compare scores alongside symptoms, functioning, safety, treatment changes, and major events. For a practical approach, see how to track mental health over time.
The useful bottom line
You cannot diagnose depression from a webpage or a questionnaire. You can notice a sustained pattern, record it clearly, and bring it to someone who can assess the full picture. Seek help based on symptoms, functioning, and safety, not only on whether a score crosses a line.