Clinical assessment

How depression is diagnosed

Depression is not diagnosed from one symptom or a questionnaire score alone. A professional considers the history, duration and severity of symptoms, their impact and alternative explanations.

This page explains what happens in an initial assessment and why questions cover several areas of life.

Before a consultation, note the main changes, when they began, current medicines and what is most difficult now.

Clinical interview and history

The professional asks about mood, interest, sleep, appetite, energy, thinking, behaviour, duration and previous episodes. Stress, support, physical health, medication, alcohol and other substances also matter.

Severity is not just a symptom count

Assessment includes the impact on work, study, relationships, self-care and safety. The same number of symptoms can affect two people very differently.

Other explanations to consider

Bipolar disorder, anxiety, grief, trauma, sleep disorders, physical illness, medicines and substances can produce overlapping symptoms. Further tests are used when clinically indicated.

The role of PHQ-9

PHQ-9 can structure self-report and monitor change but does not confirm a diagnosis. Its result must be interpreted with the clinical picture and safety assessment.

After the assessment

The professional explains the working conclusions and agrees next steps, which may include monitoring, therapy, medical review, further assessment or a treatment plan.

Common questions

A video consultation can support a full clinical assessment when the professional can gather information safely.

A self-completed online test does not establish a diagnosis.

No blood test confirms depression on its own.

Laboratory tests may be used to investigate physical causes of similar symptoms.

No. PHQ-9 is a screening and monitoring tool, not a standalone diagnosis.

The score is considered alongside symptoms, functioning, history and risk.

An initial assessment often begins at the first consultation, but further appointments or tests may be needed.

Timing depends on complexity, coexisting conditions and available medical information.

Medical sources

This material is based on the clinical sources listed below.

Would you like a professional assessment?

A consultation can review symptoms, safety and possible causes in a structured way.

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