Germanwings: Should there be screening for mental illness at work?
The deaths of 150 people aboard Germanwings flight 9525 was tragic enough, but the possibility that the co-pilot deliberately crashed the plane brought a new level of disbelief.
There has been a huge focus on the psychiatric history of the pilot and calls for greater screening for psychiatric disorders at work.
But what is screening, can psychiatric disorders be screened for, and is this the best response to the tragedy of Flight 9525?
Can you screen for depression?
Screening is the assessment for a disorder in an individual who has no symptoms and who does not know they are ill. For example, in the UK screening for certain types of cancer, such as breast or cervical cancer is now mainstream.
There are a number of well-established principles in medical screening, including that there should be a "latent" or hidden stage where the disorder is present but not apparent to the individual.
It is easy to see how the early stages of some cancers fulfil these criteria but what about psychiatric disorders like depression?
Mental health problems at work are certainly important - mental ill health at work costs the UK economy £70bn-£100bn per year and impacts negatively on the lives of patients, their families, their colleagues and employers.
However, just as patients with psychiatric disorders are more likely to be the victims than the perpetrators of violence, psychiatric illness at work impacts most on individual sufferers.
Nevertheless "something must be done" is an understandable response to the events of 24 March 2015 and there have been calls for greater levels of screening for mental health problems in certain professional groups.
Psychiatric disorders can't really be "screened" for. There is no recognised "latent" phase. Moreover, psychiatric diagnoses are based largely on symptoms, so the concept of "symptom-free" depression, for example, is difficult to sustain.
Hinder, not help
There are more practical problems too, impacting on wider public mental health.
Psychiatric disorders are among the most stigmatised of all, even in the 21st Century, and any large-scale efforts to "flush out" employees with mental disorders are likely to result in a reduced rather than a greater willingness to seek help.
There are no scans or blood tests for mental disorders, so making a diagnosis can be difficult, subjective and at times prone to error.
A screening programme will produce many "false-positives" - people labelled with a psychiatric disorder who do not in fact have one. This may have significant adverse impacts for them, and may cause greater harm than not identifying the small number of "true-positives".
It is not "screening" for mental ill health at work that is needed but earlier recognition and better access to treatment.
At present, many people with a mental disorder are never diagnosed as such, and very few of those with more common disorders such as depression and anxiety receive any treatment. This would be a scandal in any other area of medicine.
There is good evidence on what aspects of the workplace can lead to mental ill health.
High demands, low control over your work, an imbalance between what you feel you put in and what you feel you get out, low levels of support - these have all been shown to lead to higher levels of mental illness at work.
These workplace issues are in addition to the well-recognised individual risk factors for psychiatric illness, such as a difficult early life, low educational attainment and chronic physical ill health.
We should also remind ourselves that the workless population, especially those recently made unemployed, are at greater risk of psychiatric illness than those in work - psychiatric disorders cluster with other social factors to keep people at the bottom of society.
Although the clamour for greater screening for mental illness at work is understandable, in my opinion it is unlikely that screening per se would have prevented the terrible loss of life on board Flight 9525.
There are better and more cost-effective ways to reduce the impact of mental illness at work.
Greater focus on using our current knowledge to make workplaces healthier, establishing clear confidential pathways for employees to be referred or self-refer if there are concerns about their mental health (such as the Practitioner Health Programme for doctors and dentists), and increasing the proportion of patients able to benefit from both antidepressant medication and talking therapies, all have the potential to improve mental health.
And it shouldn't really take an issue like Germanwings Flight 9525 to remind us how important mental health is for us all.
Dr Max Henderson is a senior lecturer and consultant psychiatrist at King's College London, Institute of Psychiatry, Psychology & Neuroscience.