Depression is a mental health condition involving persistent low mood, loss of interest or pleasure, and changes in thinking, sleep, appetite, energy, and daily functioning. It is more than ordinary sadness, although it can follow grief, stress, trauma, illness, isolation, or major life changes.
Depression can be mild, moderate, or severe. It may happen as a single episode, return in episodes, or become long-lasting. It can affect work, study, relationships, self-care, physical health, and safety.
Symptoms
Common symptoms include:
- Low mood, sadness, emptiness, or hopelessness.
- Loss of interest or pleasure.
- Tiredness or low energy.
- Sleep problems, including insomnia or sleeping more than usual.
- Appetite or weight changes.
- Poor concentration or difficulty making decisions.
- Feelings of guilt, worthlessness, or failure.
- Slowed movement or agitation.
- Loss of sex drive.
- Thoughts of death, self-harm, or suicide.
Physical symptoms can also occur, including aches, digestive problems, headaches, and changes in movement or speech. Symptoms vary, and some people mainly show irritability, withdrawal, anxiety, or reduced functioning rather than obvious sadness.
Causes and Risk Factors
Depression usually has more than one cause. Risk can be affected by:
- Family history and genetics.
- Previous depression or other mental health conditions.
- Trauma, abuse, bereavement, bullying, or severe stress.
- Loneliness or lack of support.
- Long-term physical illness or pain.
- Alcohol or drug misuse.
- Some medicines or hormonal changes.
- Financial pressure, work problems, housing insecurity, or relationship conflict.
Depression is not a simple chemical imbalance. Brain chemistry, psychology, body health, environment, and life history can all matter.
Diagnosis
Diagnosis is based on symptoms, duration, impact on life, risk assessment, and clinical judgement. There is no single blood test for depression, although tests may be used to look for other causes of symptoms, such as thyroid disease, anaemia, vitamin deficiency, or medication effects.
Clinicians may use questionnaires such as PHQ-9 to measure symptom severity, but questionnaires are tools rather than the whole diagnosis.
Treatment
Treatment depends on severity, preference, previous response, risk, and access to care. Options can include:
- Guided self-help and supported online programmes.
- Talking therapies, including cognitive behavioural therapy.
- Behavioural activation and structured activity planning.
- Antidepressant medicines.
- Combined therapy and medicine for more severe depression.
- Support for sleep, alcohol use, social isolation, work, debt, or physical health problems.
- Specialist mental health care for severe, psychotic, chronic, or treatment-resistant depression.
NICE guidance separates less severe and more severe depression and recommends matching treatment to the person's needs and preferences. WHO notes that psychological treatments are first treatments for depression and that antidepressants can be combined with them in moderate and severe depression.
Risk and Crisis
Depression can increase suicide risk. Thoughts of self-harm or suicide need to be taken seriously, especially where there is a plan, intent, previous attempts, severe agitation, intoxication, psychosis, or lack of support.
In the UK, urgent help may involve NHS 111, a GP urgent appointment, a local crisis line, A&E, or 999 where there is immediate danger.
See Also
References
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