Almost one in seven airline pilots are suffering from depression, research has revealed.

The first study of pilots' mental health was carried out after clinically depressed Andreas Lubitz last year steered Germanwings flight 4U 9525 into the French Alps, killing 150 people.

It shows almost 14 per cent of working pilots meet the threshold for depression, reporting symptoms like suicidal thoughts, trouble concentrating and feelings of failure.

A 'veil of secrecy' has been drawn over pilots' mental health, according to researchers at Harvard T.H. Chan School of Public Health.

The study authors, who surveyed people in the UK and internationally, say long flights can disrupt sleeping patterns while flying a plane is categorised as a high-stress job. But the stigma of seeking help, for fear of being 'grounded', may be putting pilots off having treatment.

Senior author Joseph Allen, assistant professor of exposure assessment science, said: 'We found that many pilots currently flying are managing depressive symptoms, and it may be that they are not seeking treatment due to the fear of negative career impacts.

'There is a veil of secrecy around mental health issues in the cockpit. By using an anonymous survey, we were able to guard against people's fears of reporting due to stigma and job discrimination.'

Co-author Alex Wu said: 'This is important to address, so that we can hope to mitigate, or even prevent, future incidents similar to the Germanwings incident.'

The figure of one in seven is higher than the incidence of depression in the population at large. Studies in the US have suggested one in ten adult will suffer depression at some point in their lives, but no more than around six per cent at any one time.

A previous study published in the journal Aerospace Medicine and Human Performance looked at 65 cases of pilot suicide and 18 cases of homicide-suicide, where passengers died, mostly after a pilot was left in the cockpit alone.

They found pilots killed themselves and others when driven by conflict at work, relationship and financial problems, among other factors.

The latest study states that pilots may become depressed through sleep disturbance from flying at night, which upsets their circadian rhythms. Those using sleeping aids were more likely to suffer from depression, and rates are similar to those seen in other high-stress jobs like the military.

The researchers surveyed at random 1,848 pilots on their mental health, with 13.5 per cent who had worked as a pilot within the last week meeting the criteria for depression. Of these, more than four per cent said they had suffered suicidal thoughts within the last fortnight.

Around 95 per cent of pilots are men, and those in their forties are most at risk, the study found.

Previous research has found pilots have a lower incidence of depression, but underreporting of symptoms has been found in previous tragedies.

The study states: 'Underreporting of mental health symptomsand diagnoses is probable among airline pilots due to the public stigma of mental illness and fear among pilots of being 'grounded' or not fit for duty.'

However the research also uses self-reported signs of depression, rather than medical records, which experts say produce a high incidence of symptoms wrongly interpreted as depression.

Professor Sir Simon Wessely, President of the Royal College of Psychiatrists, said: 'I know of little or no evidence that pilots are more at risk of depression than other occupational groups, and instead it is likely that they have less because of stringent medical checks and drug and alcohol checks.

'It is likely that the causes of depression are similar in pilots as in the rest of us - background, upbringing, relationships etc.' 

Courtesy Daily Mail