WHO estimates that depression affects hundreds of millions of people worldwide and is a leading cause of disability. It’s especially common among people with long-term physical illnesses such as diabetes, heart disease, HIV, cancer, stroke and chronic pain, and it worsens outcomes for those conditions. Yet depression is frequently missed in general health settings. Nurses, who spend time with patients and often hear what they don’t tell doctors, are well placed to notice.
Core symptoms
The two core features are:
- Persistent low mood most of the day, nearly every day.
- Loss of interest or pleasure in usual activities (anhedonia).
Other symptoms include changes in sleep and appetite, fatigue, poor concentration, feelings of worthlessness or guilt, slowed movement or restlessness, and thoughts of death or suicide. Symptoms lasting at least two weeks and affecting daily life suggest a depressive episode.
Depression can look different
- Physical complaints: in many cultures, people describe depression through the body: headaches, “heat in the head”, tiredness, body pains, poor sleep. These may be the main presenting complaint.
- Older adults may show withdrawal, memory problems or loss of appetite, mistaken for dementia or “just ageing”.
- Men may present with irritability, anger, alcohol use or risk-taking.
- Adolescents may show irritability, school problems and withdrawal.
- Perinatal women: see our perinatal mental health guide.
Screening tools
The PHQ-2 asks two questions about the past two weeks:
- How often have you been bothered by little interest or pleasure in doing things?
- How often have you been bothered by feeling down, depressed or hopeless?
Each is scored 0 (not at all) to 3 (nearly every day). A score of 3 or more suggests further assessment with the PHQ-9, a nine-item questionnaire (scores 0–27) that helps gauge severity: roughly 5–9 mild, 10–14 moderate, 15–19 moderately severe, 20+ severe. Item 9 asks about thoughts of self-harm and must always be followed up. Screening tools support, but don’t replace, clinical assessment. Validated translations exist in many languages.
Starting the conversation
- Find privacy and time.
- Use open questions: “How have you been feeling in yourself lately?” “How are you coping with everything?”
- Normalise: “Many people with long illnesses feel low. It’s common and treatable.”
- Listen without rushing to reassure.
- Be aware of stigma: some patients fear being labelled “mad” or weak. Use language that fits the patient.
Always ask about safety
Asking directly about suicidal thoughts does not increase risk. “Sometimes when people feel this way, they have thoughts of ending their life. Have you had thoughts like that?” If yes, assess further and escalate according to policy. See our suicide risk guide.
Treatment
- Psychological therapies: CBT, behavioural activation, problem-solving therapy, interpersonal therapy. WHO has developed scalable approaches, such as Problem Management Plus, that trained non-specialists can deliver.
- Antidepressants (e.g. SSRIs) for moderate to severe depression. Effects take a few weeks; side effects often appear first. Patients shouldn’t stop suddenly.
- Physical activity, sleep routines, social contact and addressing practical problems (money, housing, violence).
- Treat physical causes: hypothyroidism, anaemia, vitamin deficiencies, medicine side effects.
WHO’s mhGAP Intervention Guide supports nurses and other non-specialists in primary care to identify and manage depression where mental health specialists are scarce.
Practical nursing support
- Encourage small, achievable activities.
- Monitor eating, drinking and sleep.
- Involve family (with consent).
- Watch medicine adherence for both physical and mental health conditions.
- Document and refer appropriately.
And remember: nurses experience depression too. If these symptoms describe you, please reach out for support.
Related: Anxiety and panic attacks · Nurse burnout
Based on WHO depression fact sheets, the WHO mhGAP Intervention Guide, NICE NG222 (Depression in adults) and the PHQ-9. Educational content.