Biological marker for depression in teens – experts respond

Teenage boys who show a combination of depressive symptoms and elevated levels of the ‘stress hormone’ cortisol are up to fourteen times more likely to develop major depression than those who show neither trait, according to new research.

sadyouthIn a study published today in the Proceedings of the National Academy of Sciences, researchers from the University of Cambridge have identified the first biomarker – a biological signpost – for major, or clinical, depression. They argue that this could help identify those boys in particular at greatest risk of developing the illness and provide treatment at an earlier stage.

The researchers hope that having an easily measurable biomarker – in this case, elevated cortisol plus depressive symptoms – will enable primary care services to identify boys at high risk and consider new public mental health strategies for this subgroup in the community.

Our colleagues at the UK SMC collected the following expert commentary.

Dr Oliver Howes, Spokesperson for European College of Neuropsychopharmacology (ECNP) and Consultant Psychiatrist, Institute of Psychiatry / Maudsley Hospital, King’s College London, said:

“Depressive disorders are amongst the top causes of suffering and disability in the world. They are also incredibly costly to society. The 2011 European College of Neuropsychopharmacology report found mood disorders cost Europe over 110 billion Euros each year; the equivalent of the 2010 Greek bailout, every year. For these reasons we desperately need ways to identify people at high risk of depression early so we can potentially prevent its onset and treat it early to reduce its burden. In this context the study by Owen et al is a landmark in the field.

“It raises the real possibility that we could identify people at high risk of depression early. Their approach, based on a spit sample and some questions, is also elegant in its simplicity and potential to be used across settings. It’s also interesting that their risk marker was specific for men as depression is harder to pick up in men. The study is an important first step, but it is also important to realise it will take a lot of further work and funding before we get a test that can be routinely used in clinical practice”.

Dr John Williams, Head of Neuroscience and Mental Health, Wellcome Trust, said:

“Progress in identifying biological markers for depression has been frustratingly slow, but now we finally have a biomarker for clinical depression. The approach taken by Professor Goodyer’s team may yet yield further biomarkers. It also gives tantalising clues about the gender differences in the causes and onset of depression.”

Comment from AusSMC

Professor Philip Mitchell is Principal Researcher at the Black Dog Institute and Head of the School of Psychiatry, UNSW.

“We have traditionally found it difficult to determine which young people are at increased risk of developing clinical depression, which means we have been unable to target interventions specifically to those that will need them.

“This significant study has shown that a relatively simple process might help us to identify the young men who will go from displaying mild symptoms of depression to life-threatening clinical depression.

“This finding suggests that trials of early intervention should be focussed on boys with this particular profile.”

Science Media Centre (UK) Fact Sheet – Depression


Depression is a long lasting low mood that interferes with the ability to function, feel pleasure, or take an interest in things, and not something sufferers can “snap out of”. Depression can be mild, moderate or severe. In its severe form, major (clinical) depression is a mental illness which can be life threatening due to the risk of subjects committing suicide or neglecting to eat and drink.

Some cases fit well-recognised patterns, such as post-natal depression and seasonal affective disorder, and depression can occur within distinct mental health conditions like bipolar disorder.

Who does it affect?

Around 1 in 10 people* in the UK experience some form of depression in their life, and more women are diagnosed with depression than men. Many people will experience only one or two depressive episodes, but about 1 in 5 people do not benefit from any antidepressant strategies and so their condition becomes chronic.

Different factors are thought to contribute towards depression, such as genetics, brain chemistry, lifestyle and upbringing. Key triggers include stressful life events, medical illness and alcohol abuse.


Symptoms include persistent sadness, constantly feeling tired, lack of sleep, poor appetite, low sex drive, and aches and pains. Sufferers may also lack motivation and have low self-esteem. A sufferer of major depression may experience suicidal thoughts, may self-harm and can be at risk of suicide.

How is it recognised?

There are currently no physical tests for depression but a GP may use urine or blood tests to rule out other conditions with similar symptoms (e.g. having an underactive thyroid). The main way depression is diagnosed is through questions about a person’s general health and how their feelings affect them mentally and physically. Various scientifically validated scales exist for measuring depression.


Treatments for more severe depression include antidepressant medication and talking therapies, such as cognitive behavioural therapy (CBT), while treatment for milder cases include exercise therapy and self-help groups. Electroconvulsive therapy (ECT), though rarely used and often misunderstood, is the most effective treatment for the severest forms of depression and can be life-saving.

*2000 figure for UK. New Zealand’s ‘Dunedin’ cohort study of 1037 people from 2005- puts this figure at 1 in 6.

This is a fact sheet issued by the Science Media Centre (UK) to provide background information on science topics relevant to breaking news stories. This is not intended as the ‘last word’ on a subject, but rather a summary of the basics and a pointer towards sources of more detailed information. These can be read as supplements to our roundups and/or briefings.