Causes of depression

There is no single known cause of depression. Current explanations tend to lie in a combination of brain chemistry, genetic and environmental factors.

The information from this page and more can be found in the Depression factsheet (228 kb) [pdf]

Biochemical

It is known that in people experiencing depression, there is a change in their brain messaging chemicals.

These chemicals are important in regulating mood and various other important functions. When an imbalance of brain chemicals occur, it is believed that depression can result, although it is also possible that the chemical change is the result of depression.

Genetic

Some types of depression, like major depression, run in families, suggesting that some element of depression may be inherited, although there is no single depression gene.

Hormonal

Hormones are also chemical messages that communicate within the body as a whole and are thought to contribute to mood.

Environment/ background

Certain environmental causes such as family factors and adverse childhood experiences are considered to increase a person's chance of developing depression which can lead to negative thought patterns and low self esteem.

Lifestyle

  • Food

There has been more attention in recent years to the effect that food and drink can have on our mental wellbeing. Certain foods contain “essential fatty acids” which help keep the brain healthy and regulate mood. Other foods are known to have a detrimental effect on mood.

  • Exercise

As well as being essential to your physical health, exercise regulates blood sugar, improves mood stability releases mood enhancing endorphins. 

  • Substance misuse

Excessive substance use can affect the functioning of the brain and some research suggests this can have long lasting results. Excessive alcohol consumption is thought to be linked with depression due to depleting essential fatty acids in the brain. 

For more information about the link between physical health and mental illness please see our Physical Health and Nutrition Factsheet (542 kb) [pdf]

Hanging basket  

Physical illness 

Mood change and depression are more common in people suffering from physical illnesses than in people who are well. The link between physical illness and depression could be attributed to several factors, perhaps interacting with each other. It is also more common amongst people with a number of forms of chronic illnesses, and so should be an important consideration in treatment plans. For more information see our factsheet on Physical causes of mental illness and depression

Medication and depression

There is a lot of disagreement in medical literature about the role of prescribed medications in inducing symptoms of depression. However, review of research has suggested that the following drugs may be associated with depression: Beta-blockers. Corticosteroids, Calcium channel blockers, Levodopa.

Rethink Advice and Information Service factsheet

Factsheet 2011 image

This information comes from the Rethink Advice and Information Service Depression factsheet  to see and download other factsheets please see Factsheets A-Z