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Causes - Clinical depression

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

Traumatic or stressful life events can cause clinical depression.

These include:

  • bereavement
  • divorce
  • illness
  • losing your job
  • 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 cause clinical depression.

A 'downward spiral' of events can 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.

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 also stop seeing your family and friends, the risk increases.


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. Your personality can be a result of the 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 after a birth can affect how you feel. The stress and responsibilities of a new life can add to a low mood.

Learn more about postnatal depression


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

Learn more about loneliness

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 and your brain is still developing.

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

More information and support is available on the following websites:


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.

An overactive thyroid also increases the risk of depression.

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

Page last reviewed: 1 September 2022
Next review due: 1 September 2025