Causes of depression

What causes depression?

There is no single cause of depression. Depression is a complex mental health condition that can affect anyone, and it’s usually caused by a combination of different factors.

These factors can include things that happen in our lives, our physical health, our biology and the support we have around us. For some people, there may be a clear reason they begin to feel depressed, such as a stressful life event or a period of change. For others, depression can develop without an obvious cause.

Some factors that may contribute to depression include:

Biology and hormones

Our bodies and brains play an important role in how we think, feel and respond to the world around us. Changes in hormones, genetics and other biological factors can influence our chances of experiencing depression.

Some people experience changes in their mood during times of hormonal change, such as puberty, pregnancy, after having a baby or during perimenopause and menopause. Low levels of certain nutrients, including vitamin B12, have also been linked with symptoms of depression in some people.

Family history and genetics

Depression can sometimes run in families. Having a close family member who has experienced depression may increase your likelihood of experiencing it yourself.

However, having a family history of depression does not mean you will definitely develop it. Genetics are only one part of the picture, alongside your experiences, circumstances and environment.

Stressful life events and experiences

Difficult experiences and stressful events can affect our mental health. These may include bereavement, relationship difficulties, financial worries, unemployment, illness, caring responsibilities, trauma or major life changes.

Experiences during childhood, including abuse, neglect or ongoing stress, can also affect mental health later in life and may increase the risk of depression.

Social and environmental factors

The circumstances we live in can affect our mental health. Factors such as loneliness, isolation, discrimination, poverty, insecure housing, work pressures or a lack of support can all contribute to feelings of stress and low mood.

Lifestyle and physical health

Looking after your physical health can support your mental wellbeing. Research suggests that regular physical activity, eating a balanced diet, getting enough sleep, staying connected with others and making time for activities you enjoy can all help support good mental health.

Smoking, harmful alcohol use, drug use, poor sleep and a lack of physical activity may also be linked with a higher risk of depression for some people.

However, lifestyle factors do not mean someone is responsible for their depression. Many people who experience depression already have healthy lifestyles, and depression can happen to anyone.

Other health conditions

Living with a physical health condition, especially a long-term, painful or life-threatening illness, can affect your mental health. Some conditions affecting the brain, including brain injuries and dementia, can also involve changes in mood and emotions.

Sleep

Sleep and mental health are closely connected. Poor sleep can affect how we feel, think and cope with everyday challenges, and ongoing sleep problems can increase the risk of experiencing depression.

At the same time, changes to sleep are also a common symptom of depression, so it can sometimes be difficult to know which comes first.

Substance use

Alcohol and drugs can affect mood, sleep and how the brain processes and manages emotions. Some people may use substances to cope with difficult feelings, but this can sometimes make symptoms of depression worse over time.