SA Forum is an invited essay from experts on topical issues in science and technology.

Since the Germanwings plane crash, speculation has focused on the co-pilot, Andreas Lubitz, and what role mental illness might have played in this horrible tragedy. This question has been magnified by the emergence of information that he had a past history of psychiatric or psychological treatment for what was reported to be depression and suicidal ideation and that his doctors had recently recommended that he take medical leave from work for as yet undisclosed ailments—advice he apparently disregarded. His employer, Lufthansa, acknowledged that it had been aware that Lubitz had experienced a serious depressive episode prior to his completion of pilot training in 2009. It is also clear that his obscene behavior was premeditated and planned and was not an impulsive or spontaneous act.

This information has raised four key questions: What was the nature of Lubitz’s mental disturbance? What was its relevance to his murderous act? What should Lufthansa have done in light of their knowledge of his situation? And what were his doctors’ responsibilities?

First, it should be said that because the available information thus far is fragmentary, incomplete and unconfirmed, any discussion of these questions should be considered speculative. 

We do not know what Lubitz may have suffered from when he interrupted his flight training or in the period just prior to crashing the plane and killing 150 people. The most likely possibilities include depression, anxiety or a PTSD-like stress disorder. According to news reports, he also had a non-psychiatric medical condition affecting his eyes, which could have impaired his ability to fly and perhaps provoked an untoward mental reaction at the prospect of losing his career. It’s also possible that he was using drugs (recreational or prescription) that affected his mental function. Whatever the case, his recent symptoms were not so severe as to warrant hospitalization or disrupt his behavior to the extent that it was overtly apparent to co-workers and friends. Thus, whatever Lubitz suffered from, he was able to contain and conceal it for the most part.

It is even less clear how any mental problem from which Lubitz may have suffered figured into his plan to destroy the plane and commit suicide and murder. A person is motivated to perform such horrific acts for one of three reasons. One is that they are ideologically motivated (like the 9/11 destruction of the World Trade Center or Timothy McVeigh’s bombing of the Murrah Federal Building in Oklahoma City). The second is as an act of passion or revenge (like the disgruntled employee fired from his job who retaliates by shooting his boss and co-workers). The third reason is mental illness, which in most cases is due to psychosis. Mentally ill persons who have committed the shocking civilian massacres that have occurred in recent years (think Adam Lanza, Jared Loughner, James Holmes) usually do so because they are impelled by their hallucinations and/or delusions. There is no evidence, however, that Lubitz was psychotic.

It’s possible that severe depression can distort a person’s perception of reality and judgment to the point that they could take such desperate actions. One such instance was in 2001, when Andrea Yates drowned her five children while in the throes of a post-partum depression with psychotic symptoms. But, such instances are rare and Lubitz showed no signs of such extreme mood disturbance.

So what was Lufthansa’s responsibility and what could it have done to prevent this tragedy? Pilots, like all people who are in positions of responsibility for the lives of the public, must undergo regular medical evaluations and they have a responsibility to inform their employer of any ailment that could influence their ability to capably perform their job. This holds true for all conditions such as heart disease and asthma, as well as mental disorders like depression. However, the critical question is not whether someone has had an illness but whether it has been adequately treated and they are actively symptomatic or not. With some exceptions (commercial pilot licenses are not available to people with Type 1 diabetes or epilepsy), we do not prohibit people from jobs just because they have an illness, unless its symptoms impair their ability to function adequately. Presumably if someone is receiving treatment for hypertension or depression and their symptoms are under control, they should be able to fly a plane provided they are not taking medications banned by aviation authorities. The critical factors are close monitoring and full disclosure.

So the question is, did Lufthansa conduct adequate medical surveillance of its employees and particularly its pilots, including their psychiatric status? The airline is undoubtedly reviewing these procedures. An additional question concerns the role of Lubitz’s doctors. Was there more they could have done to insure that he took the recommended leave from work, short of hospitalizing him? If they were physicians to whom he was referred by the airline, presumably they would have notified the company of their findings and recommendations. If he had engaged these doctors on his own initiative, they may have had a duty to warn the airline if they knew that he was an airline pilot and believed that he was sufficiently impaired to pose a danger to himself or others. However, the decision about whether to breach doctor-patient confidentiality is always a complex judgment and in this case depends on legal standards and medical practices in Germany.   

In general, someone who has a prior history of depression but has been effectively treated and is no longer symptomatic should not be prohibited from working. That kind of absolute prohibition would further stigmatize mental illness. Moreover, it would deter people from seeking treatment and being forthcoming with their doctors. The value of openness about mental health risks for pilots has been demonstrated in the U.S. Air Force: After it required annual suicide awareness and prevention training in 1995, suicides among service members fell from about 15 per 100,000 to about 9. 

Further lessons will undoubtedly emerge as we learn more about the Lufthansa tragedy. But this much we already know: forcing people to go underground with their mental illness will not make us safer in the air—or anywhere else.

Jeffrey Lieberman, M.D., author of Shrinks: The Untold Story of Psychiatry (Little Brown and Co., 2015), is chair of psychiatry at Columbia University Columbia University Medical Center and psychiatrist in chief of the New York Presbyterian Hospital as well as the immediate past President of the American Psychiatric Association.