According to media reports, psychiatric illness stalked Andreas Lubitz, the 27-year-old Germanwings pilot who crashed an Airbus A320 into the French Alps three days ago, killing himself and the other 149 people aboard. During his training in 2009 at Lufthansa Flight School, Lubitz reportedly was deemed temporarily unfit to fly, and he battled major depression for 18 months. 

I have treated several surgeons, police officers and an airline traffic controller who kept working while battling depression, as well as a few who stepped down or took time off on my advice.

For those who wonder how Lubitz, if suffering with severe depression again, could have seemed fit to fly to those around him, consider this: I have treated several surgeons, police officers and an airline traffic controller who kept working while battling depression, as well as a few who stepped down or took time off on my advice. Those who stayed on the job were able to perform admirably, without a hitch in their distinguished careers, while confronting profound sadness, wondering whether life was worth living, taking multiple psychiatric medications and talking with me as often as every day, for some periods.

I have treated several surgeons, police officers and an airline traffic controller who kept working while battling depression, as well as a few who stepped down or took time off on my advice.

Major depression can commandeer a person’s emotions and thoughts while the person is careful not to let most others know. This is partly because the person can be profoundly ashamed of his inability to overcome the darkness he is feeling inside, motivating him to keep it a secret. It is partly because depression can shred the person’s belief in himself and the value of life, while leaving his intellect and ability to perform complex tasks nearly intact — meaning work performance can be the last strength to wither. And it is partly because depression can take a turn for the worse very quickly, suddenly crystallizing in desperation after one more sleepless night, or one final rejection from a girlfriend, or one last time hoping to enjoy an evening with one’s children, only to feel emptiness and despair.

And all this leaves aside the fact that major depression can also cause delusions — fixed and false beliefs that can trigger very complex, perfectly executed behaviors that are also completely irrational. I have treated a depressed lawyer who came to believe that the CIA was stalking him and employed elaborate strategies to avoid being followed. I have treated a depressed entrepreneur who believed he was financially ruined and visited several accountants to prepare for bankruptcy, while still possessing extraordinary financial wealth. I have treated an executive who believed he was about to be wrongly charged with murder, despite there being no evidence whatsoever that the police suspected him of anything at all. I have treated a depressed woman who believed she was dying of cancer (with no objective evidence whatsoever) and painstakingly prepared her will.

For all these reasons, it is not enough (though it is often all that is done) to treat a person suffering with depression so severe that it renders him unable to operate an aircraft, and then welcome him back to work after a waiting period. I would argue that that person, when returning to work, should be monitored by a psychiatrist who can communicate with his employer, from that point, until his career has concluded. This wouldn’t mean that the pilot would never experience depression again, but it would mean that recurrences could be treated early, that time off could be arranged when needed to maintain health and that family members could be included as part of the necessary safety net.

If Andreas Lubitz committed suicide by downing the aircraft he was flying, taking 149 other lives, he would not be the first pilot to commit suicide by intentionally crashing. According to an FAA study, of 2,758 aviation accidents from 2008 to 2012, eight were determined to be suicides. That is one-third of one percent. And while some sources call that rare, I do not.

One in a million is rare. One out of 345 is startlingly common.

Dr. Keith Ablow is a psychiatrist and member of the Fox News Medical A-Team.