What can cortisol reveal about depression?

Written by Linzasaur

Around one in six people suffer from depression at some stage in their lives, and most of us will have known somebody with a mental illness.

Around one in six people suffer from depression at some stage in their lives, and most of us will have known somebody with a mental illness. In the UK alone, as many as 10 million people could develop a mental health problem in their lifetime. Three quarters of mental health diseases start before people are even 24 years old, which contradicts the idea that younger is fitter.

Thankfully in recent years, it has been recognised how serious and affecting having a mental illness can be, and there has been a great deal more interest and research into the underlying causes of the problems.

It has been realised how important and influential the human mind is on our health and wellbeing, including research into how extreme loneliness can perhaps be even worse for physical and mental health than obesity.

Trying to break it down

Researchers at the University of Cambridge have discovered a ground-breaking new way of identifying the teenage boys who are most likely to develop clinical depression later on in life.

The cause of depression is something that has baffled doctors for years and although advances in medication are getting steadily more effective, the underlying reason for the disease has very much been a mystery.

 However, recent research has found the first biomarker for clinical depression. A biomarker is a naturally occurring molecule, gene, or characteristic in our bodies by which a particular pathological or physiological process or disease can be identified. For depression in teenage boys, the biomarker could be the stress hormone cortisol.

By identifying the problems earlier on in life, preventions and interventions can be targeted at these individuals and hopefully help to reduce their risk of serious episodes of depression in adult life. Hopefully this will provide a giant leap forward in the successful treatment of mental illness in the future.

Currently, cortisol as an indicator only works for male participants, as cortisol levels are naturally higher in women than men. There has not yet been an equivalent way discovered of predicting outcomes for female patients.

The study was performed by researchers by analysing several saliva samples taken at early morning within a week from more than 1,850 teenagers, and was repeated year later. The samples showed that the cortisol levels of each individual were constant over the year and were then compared with the symptoms of depression each participant was reported to have.

The study found that teenage boys who had a combination of depressive symptoms and raised levels of cortisol were up to 14 times more likely to develop clinical depression than those who demonstrated neither trait.

Location, location, location (of the cause)

Cortisol is the hormone that is released by the adrenal gland, and is most commonly associated with physical or emotional stress, or the ‘fight or flight’ response in animals to aid in survival against threats such as predators. Levels of the hormone also rise in times of uncertainty in humans.

A recent study, also at the University of Cambridge, has discovered that high levels of cortisol are likely to make traders wary of taking risks when things get difficult, which can apparently ‘make the financial crisis worse.’

Cortisol has also been associated with various types of separation, particularly with a mother and baby. There is a considerable increase in cortisol among both the mother and the child following maternal separation.

A recent study has found that cortisol is also present in breast milk and appears to affect babies differently depending on their sex. A study on laboratory monkeys has found that the level of cortisol in breast milk is variable between mothers and that it affects sons and daughters differently.

Female babies who had high levels of cortisol in the milk they were given showed more irritability, fear and anger, which was not apparent in males who were fed on breast milk with similar concentrations of the hormone. The researchers believe that similar results would also be true for human breast milk.

As there is further research into the causes of depression, it will be interesting to observe how many factors are taken into account, and whether something as natural and unassuming as breast feeding might have an effect on how we behave later on in life.

With so many different processes going on inside us all the time, it can be difficult to pinpoint exact causes of problems, but scientists are definitely getting closer than ever before to the prevention of depression.

What do you think about this research? Can prevention to depression be created? Have your say in the comments section below.

Image: Benjah-bmm27 / Wikimedia Commons