The causes of depression are not fully understood, but we do know that a combination of psychological, social, genetic and biological factors can contribute to its development.
Some people have an increased risk of developing depression, due to their genes, biology or personality type.
This does not mean these people will automatically develop depression, but in these cases dealing with life events are more likely to trigger an episode of depression.
- Genetics — people with a history of depression in their close family members have an increased risk of developing depression, due to genetic factors. No single gene is responsible, but it is caused by a combination of genes.
- Hormones — hormone changes during pregnancy, after you have a baby, during menopause and if you have thyroid problems can cause depression.
- Recent events — depression can be triggered by negative events such as bad news or losing a job, although usually other factors need to be present too.
- Long-term stress — ongoing issues can cause depression over time, such as abusive relationships, constant work stress and prolonged isolation. These are more likely to cause depression than isolated events.
- Personality — certain personality types are more prone to developing depression. Those with low self-esteem, perfectionist tendencies, who are self-critical or overly sensitive to criticism may be more susceptible. Beliefs such as ‘I must get people’s approval’ or ‘I must do things perfectly or not at all’ can make people vulnerable to depression.
- Serious illness — the ongoing worry and stress associated with having a long-term illness can take its toll and lead to depression. Some illnesses or medications can also directly trigger depression.
- Drug and alcohol use — can worsen depression, and sometimes leads to a vicious cycle when substance abuse is used as a coping mechanism. Depression and substance abuse often occur together and treatment is more likely to succeed if drugs and alcohol are avoided.
- Changes in the brain — some people with depression have been shown to have abnormal levels of neurotransmitters (brain chemicals) such as serotonin, noradrenaline and dopamine. Antidepressants that change these levels can be effective in treatment in some people with depression.
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Last reviewed: August 2019