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There's no single cause of clinical depression. It can happen for a variety of reasons and it has many triggers.

Traumatic or stressful life events can cause clinical depression.

These include:

  • bereavement
  • divorce
  • illness
  • redundancy
  • job or money worries

Different causes can often combine to trigger clinical depression. You may feel ill, experience a traumatic event and a bereavement close together. These events could add up and cause clinical depression.

People often talk about a 'downward spiral' - events that lead to clinical depression. For example, you break up with your partner. You feel low and stop seeing your friends and family. You start to drink more. All of this can make you feel worse and trigger depression.

Related topic

Alcohol and depression

Stressful events

Bereavement and relationship breakdown can be hard to cope with. You are more likely to become clinically depressed when stressful life events happen. If you were to stop seeing your family and friends the risk would increase.


You may be more vulnerable to clinical depression if you have certain traits. This includes people with low self-esteem or being overly self-critical. Personality can be a cause of genes you inherited, life experiences or both.

Family history

If a close family member had clinical depression, you are at higher risk of becoming depressed.

Giving birth

Some women are at risk after pregnancy. Hormones and physical changes in a woman's body can affect how she feels. The stress and responsibilities of a new life can add to a low mood.

Related topic

Postnatal depression


Being cut off from your family and friends can increase your risk of clinical depression.

Related topic


Alcohol and drugs

Some people use alcohol or drugs to cope with how they are feeling. This can increase your risk of becoming clinically depressed. Alcohol and drugs can make you feel better for a short time, but they can also lower your mood.

Cannabis can help you relax. But, it can increase your risk of becoming clinically depressed, especially when you are young.

'Drowning your sorrows' with alcohol is also not recommended. Alcohol is a depressant. This makes depression worse.


Dealing with a long illness or life-threatening illness can increase your risk. This includes having a heart attack, stroke or cancer.

Head injuries are also often a cause of clinical depression. A severe head injury can trigger mood swings and emotional problems.

An underactive thyroid can cause physical changes in your body. You can have extreme tiredness and lose interest in sex. This can lead to clinical depression.

Content supplied by the NHS and adapted for Ireland by the HSE.

page last reviewed: 23/09/2018
next review due: 23/09/2021

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