What Is Depression? Causes, Types and Where to Find Help

Many people say they feel "depressed" after a bad week. Clinical depression is different. It is a recognised health condition that can be treated, and it is nothing to be ashamed of. This article gives a plain-English overview.

What is depression?

According to the World Health Organization (WHO), depression is a common mental disorder in which a person has a low mood or loses pleasure or interest in things for long periods. It can affect relationships, school and work. The US National Institute of Mental Health (NIMH) says it can affect anyone, whatever their age, race, income, culture or education, and that ordinary sadness usually passes with time while depression does not.

MedlinePlus describes depression as more than feeling sad or irritable for a few days. It can change how a person thinks and feels, and affect sleep, eating and work.

Types of depression

MedlinePlus lists several forms:

• Major depression: low mood or loss of interest that disrupts daily life and lasts at least two weeks.
• Persistent depressive disorder: milder symptoms that last at least two years.
• Seasonal affective disorder: depression that returns with the seasons, usually starting in late autumn or early winter.
• Bipolar disorder: intense mood swings, formerly called manic depression.
• Depression with psychosis: a severe form that includes false beliefs or hallucinations.

The WHO also describes depressive episodes as mild, moderate or severe, and notes that depression can be a single episode or can come back.

What causes depression?

There is usually no single cause. The WHO says depression results from a mix of social, psychological and biological factors. Difficult life events such as unemployment, bereavement and trauma raise the risk. NIMH adds that genetic, biological, environmental and psychological factors all play a part. MedlinePlus notes that having a close relative with depression raises risk, and that in some people no clear cause is found.

Depression and physical illness are linked too. The WHO says depression is closely connected with conditions such as heart disease, cancer, diabetes and lung disease, and MedlinePlus says long-term conditions and depression can make each other worse.

How common is it?

According to the WHO, around 4% of the world's population had depression in 2023. Among adults the figure was 5.2%, and it was about 1.5 times more common in women than in men. The WHO also reports that in high-income countries only about one third of people with depression receive mental health treatment.

Can depression be treated?

Yes. The WHO says effective treatments exist, including psychological treatments and medicines, and that talking therapies are usually the first option. For moderate or severe depression, a doctor may suggest combining the two. MedlinePlus also mentions other approaches for severe cases that have not responded to other treatment, which only a specialist can arrange. A doctor decides what suits each person, and nobody should start or stop a medicine without medical advice.

Why stigma matters

The WHO points out that social stigma around mental health conditions is a barrier to getting care. Depression is a health condition, not a weakness or a character flaw. Talking to someone you trust and then to a doctor is a good first step.

When to see a doctor

See a doctor if low mood, loss of interest or hopelessness lasts most of the day, nearly every day, for two weeks or more, or if it is getting in the way of work, study, family life or relationships. Early help can make symptoms easier to manage, according to MedlinePlus.

If you have thoughts of harming yourself or ending your life, please reach out right now. You are not alone and many people have found help. Tell a trusted person, contact a doctor or counsellor, or call a crisis help line in your area. Help lines exist in both India and the United States, and a doctor or local health service can tell you which are available near you.

This article is for general education and is not a diagnosis. Do not stop or change prescribed treatment without talking to your doctor.

In an emergency, call your local emergency number (112 in India, 911 in the United States).