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Depression

Also known as Major depressive disorder, Clinical depression

Severity: VariableAffects an estimated 280 million people worldwide

This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.

What is depression?

Depression is more than low mood. It is a persistent state of sadness or loss of interest lasting at least two weeks and interfering with work, relationships and self care. It is common, treatable, and not a sign of personal weakness. Risk of self harm should always be asked about directly, because doing so does not increase risk and can save lives.

Causes

  • Interaction of genetic vulnerability and life stress
  • Changes in brain networks regulating mood and reward
  • Bereavement, trauma or chronic adversity
  • Chronic physical illness and persistent pain
  • Thyroid disease and some medicines

Symptoms

  • Persistent low mood most of the day
  • Loss of interest or pleasure in usual activities
  • Fatigue and low energy
  • Sleep disturbance, either too much or too little
  • Appetite and weight change
  • Difficulty concentrating or making decisions
  • Feelings of worthlessness or guilt
  • Thoughts of death or self harm

Risk factors

  • Family history of depression
  • Previous depressive episode
  • Chronic illness or disability
  • Social isolation and unemployment
  • Alcohol or substance use
  • Postnatal period

Diagnosis

  • Clinical interview against recognised diagnostic criteria
  • Validated tools such as the PHQ 9 questionnaire
  • Direct assessment of self harm and suicide risk
  • Screening for a history of mania to exclude bipolar disorder
  • Blood tests for thyroid function and anaemia

Treatment

  • Cognitive behavioural therapy or interpersonal therapy
  • Antidepressant medicines, usually SSRIs first line
  • Combined therapy and medication for moderate to severe illness
  • Structured exercise and sleep regulation
  • Treating alcohol use and physical contributors
  • Crisis support and safety planning where risk is present

Self care

  • Keep a basic daily routine even when motivation is absent
  • Schedule small achievable activities rather than waiting to feel like it
  • Get outside daily and keep some physical activity
  • Protect sleep timing and avoid daytime napping
  • Avoid alcohol, which worsens mood and disturbs sleep
  • Stay connected with at least one or two people
  • Take medication consistently and give it several weeks

When to see a doctor

Book an appointment if:

  • Low mood or loss of interest lasting more than two weeks
  • Sleep, appetite or concentration significantly affected
  • Struggling at work, study or home
  • No improvement after six weeks on treatment
  • Troublesome medication side effects
  • Any thoughts of self harm, however fleeting

Some symptoms need emergency care rather than an appointment. See the warning signs listed above.

Prevention

  • Treat episodes fully rather than stopping at first improvement
  • Maintain sleep, exercise and social contact
  • Limit alcohol
  • Address chronic pain and physical illness
  • Learn and use relapse warning signs
  • Continue treatment for the recommended period after recovery

Outlook

Most people recover from a depressive episode, particularly with therapy, medication or both. Improvement typically begins within four to six weeks of starting treatment. Recurrence is common, so continuing treatment for at least six months after feeling well substantially reduces relapse. Depression is highly treatable and is not a permanent state.

Common questions

How long do antidepressants take to work?

Some improvement in sleep and appetite may appear within two weeks, but mood benefit typically takes four to six weeks. Stopping early because of no immediate effect is a common reason treatment appears to fail.

Are antidepressants addictive?

They are not addictive in the sense of craving or dose escalation. Stopping abruptly can cause discontinuation symptoms, so they are tapered gradually under medical guidance.

When is depression an emergency?

Active thoughts of ending your life, a plan, or an inability to stay safe require immediate help through emergency services or a crisis line. This is urgent in the same way that chest pain is urgent.

References

  1. National Institute of Mental Health. Mental health information.
  2. World Health Organization. Fact sheets.
  3. Mayo Clinic. Diseases and conditions.

Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.