Depression: Symptoms, Assessment and Treatment

Depression is a common mental health condition that affects mood, thinking, sleep, energy and everyday functioning. It is one of the leading causes of disability worldwide and is often missed, especially when patients present with physical symptoms. Depression is treatable, and asking about suicide is an essential part of every assessment.

Core features

A depressive episode involves, for most of the day, nearly every day, for at least 2 weeks:

• Persistent low mood, and/or
• Loss of interest or pleasure (anhedonia).

Other symptoms:

• fatigue or low energy
• poor concentration
• sleep disturbance (insomnia or oversleeping)
• change in appetite or weight
• feelings of worthlessness or excessive guilt
• slowed movements or agitation
• thoughts of death or suicide

Severity (mild, moderate, severe) depends on the number of symptoms and their impact on daily life. Severe depression can include psychotic features.

Risk factors

• Previous episodes and family history.
• Stressful life events, loss and trauma.
• Chronic physical illness and chronic pain.
• Social isolation and poverty.
• Substance misuse.
• The postpartum period.
• Some medications.

Assessment

• A careful history, including mood, functioning, stressors, sleep, substance use and past episodes.
• Screening tools: for example the PHQ-9 questionnaire.
• Rule out bipolar disorder: ask about previous periods of elevated mood or overactivity, because antidepressants alone can trigger mania.
• Rule out physical causes: hypothyroidism, anaemia, vitamin deficiencies and medication effects.
• Always assess suicide risk:
  • ask directly about suicidal thoughts, plans and intent
  • ask about previous attempts
  • check access to means
  • look for protective factors
  Asking about suicide does not increase the risk.

Treatment

• Mild depression: guided self-help, physical activity, behavioural activation and psychological therapy.
• Moderate to severe depression: psychological therapy, such as cognitive behavioural therapy (CBT), and/or an antidepressant. The combination is often best for severe depression.
• Antidepressants:
  • SSRIs (for example sertraline, fluoxetine) are usually first-line.
  • Improvement typically starts after 2–4 weeks, so review early.
  • Warn about early side effects (nausea, anxiety, sleep changes), and about a possible increase in suicidal thoughts in young people early in treatment.
  • Continue for at least 6 months after remission, longer for recurrent depression.
  • Stop gradually, to avoid discontinuation symptoms.
• Severe or treatment-resistant depression: specialist care, which may include medication changes and augmentation, or electroconvulsive therapy (ECT).
• Urgent referral for high suicide risk, psychotic features, or inability to care for oneself.

Important safety points

• SSRIs increase bleeding risk, especially with NSAIDs or anticoagulants.
• They can cause hyponatraemia in older people.
• Combining serotonergic drugs (for example SSRIs with tramadol, triptans or MAOIs) can cause serotonin syndrome.
• Tricyclic antidepressants are dangerous in overdose.

Reducing stigma

Many patients, especially in South Asia, feel ashamed to talk about mental health or describe only physical symptoms such as fatigue, headaches or body aches. A warm, non-judgemental approach and clear explanation help patients accept care.

Exam pearls

• Low mood or anhedonia for 2 weeks or more is the core of a depressive episode.
• Always ask about suicide and previous manic episodes.
• Antidepressants take weeks to work; review within 1–2 weeks of starting, especially in young people.

If you or someone you know is in crisis or thinking about suicide, contact local emergency services or a mental health helpline immediately.

See also Anxiety Disorders and the psychiatry chapter of our Medicine Companion.

Test yourself

5 exam-style single-best-answer questions. Choose your answer, then tap “Show answer”.

1. Minimum duration of symptoms for a depressive episode:

   1. 3 days
   2. 1 year
   3. 6 months
   4. 2 weeks
   5. 24 hours
   Show answer

   Answer: D. 2 weeks
   Core symptoms must be present most of the day, nearly every day, for at least 2 weeks.

2. Before starting an antidepressant, which history is essential?

   1. Blood group
   2. Shoe size
   3. Previous manic or hypomanic episodes
   4. Allergy to dust
   5. Family income
   Show answer

   Answer: C. Previous manic or hypomanic episodes
   Antidepressants alone can trigger mania in bipolar disorder.

3. How long does an SSRI usually take to start working?

   1. 2–4 weeks
   2. 1 hour
   3. 1 day
   4. 6 months
   5. Never
   Show answer

   Answer: A. 2–4 weeks
   Benefit usually begins after 2–4 weeks; review early.

4. After remission, how long should an antidepressant generally continue?

   1. 2 weeks
   2. Lifelong for all
   3. Stop immediately
   4. At least 6 months
   5. 1 day
   Show answer

   Answer: D. At least 6 months
   Continue for at least 6 months after remission to reduce relapse.

5. Combining an SSRI with tramadol risks:

   1. Hyperkalaemia
   2. Hypoglycaemia
   3. Bradycardia only
   4. Hair loss
   5. Serotonin syndrome
   Show answer

   Answer: E. Serotonin syndrome
   Serotonergic combinations can cause serotonin syndrome.

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Disclaimer

For education and exam preparation only. This is not medical advice and must not be used to diagnose or treat patients. Always follow current clinical guidelines and the advice of qualified senior colleagues.