Causes & Symptoms

There are many different causes and factors that contribute to depression and each will be unique to the individual who experiences it.  Sometimes the cause is not very clear, and it may in fact involve a number of different factors that all contribute to the resulting depression.

Some causes of depression include:

• Lifestyle factors such as stress, nutrition, sleep and exercise
• Genetic predisposition
• Personality
• Traumatic event/s such as losing a loved one
• Medical conditions including hormonal disorders
• Medications/Drugs

Lifestyle factors

Many of the unhealthy lifestyle habits that contribute to illnesses such as heart disease can also trigger anxiety & depression.  High levels of stress or anxiety combined with poor eating and sleeping habits, and no exercise for prolonged periods may be a significant factor in some people’s experience of depression.

Although not normally associated with depression, nutritional deficiencies (particularly deficiencies in some of the 'B' group vitamins), intolerance to foods, additives and some chemicals may also be a contributing factor in depression for some people.

Genetic predisposition

There is strong growing evidence that genes can be a risk factor for developing depression therefore increasing the likelihood that severe environmental stresses may precipitate the onset of depression. Some personality traits, such as a propensity for high anxiety levels, may also be linked with genes.

Personality

There appears to be a link with certain personality characteristics and depression. According to Gordon Parker and The Black Dog Institute, a person who exhibits one or more of the following, may be more at risk of depression.

• experiences high levels of anxiety, is a ‘worrier’ or is irritable
• is shy or reserved
• is self-critical or has low self-worth
• is hypersensitive 
• is a perfectionist
• has a self focused style

Traumatic events

The natural grief we feel at the death of a loved one, or the breakdown of a marriage or other relationship is a healthy reaction to a stressful life event, and sadness/anxiety in these circumstances may be normal.  If the grief however is severe and continues beyond a reasonable time it may develop into clinical depression.

Medical conditions

If an illness or medical condition is life threatening, disabling or significantly affects lifestyle in a negative way, there is a possibility that depression may occur as a result of having to deal with it emotionally.  However, there are also some illnesses that are known to cause depression such as some cancers. 

The hormonal changes that occur naturally throughout life are common igniters of anxiety or depression.  The hormonal changes at puberty, during pregnancy, childbirth and menopause may cause symptoms of depression.  Illnesses that affect hormones such as Addison's disease and Cushing's disease can also trigger depression.

Illnesses that are more likely to be associated with or who present with depression include: AIDS, rheumatoid arthritis, cancer, influenza, thyroid imbalance, Ross River fever, viral pneumonia, neurological disorders, multiple sclerosis, Parkinson's disease, sleep apnoea, and stroke.

Medications/Drugs

Symptoms may take some time before they are identified as depression rather than just a rough patch and changes in medication or illicit drug taking are often overlooked when considering factors that may be causes contributing to the depression.  

It is very important to discuss any medication or drugs you are taking when discussing symptoms or causes of depression and anxiety with a healthcare professional so you can work together to reduce the symptoms as quickly and as safely as possible.

Some people experience symptoms of depression when they start taking a new medication or when stopping a medication. Taking illegal drugs is one of the common causes of depressive symptoms.

Depression is easier to treat the earlier it is detected and there may also be other explanations to causes of your depression or anxiety which is why a proper assessment by a doctor is important.

References:

Dealing with depression – A common sense guide to mood disorders
Gordon Parker
2005

Genes, stress, and depression
Metabolism Clinical and Experimental 54 (Suppl 1) (2005) 16– 19
Richard J. Wurtman

Genetics of affective (mood) disorders
European Journal of Human Genetics (2006) 14, 660–668
Nick Craddock and Liz Forty

Understanding Depression
Maria Prendergast
2006

Causes of depression
Blackdog Institute

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