David Dao, the passenger in question, is a doctor.
From the Atlanta Journal Constitution:
Dao was ultimately convicted in late 2004 of several counts of obtaining drugs (for sex) by fraud or deceit and was placed on five years of supervised probation and surrendered his medical license.
His longtime effort to get his license back finally succeeded in 2015, when the licensing board allowed him to practice medicine again.
He was also known to have mental problems, especially when dealing with difficult situations.
From the LA Times:
According to publicly available state licensing records reviewed by the Los Angeles Times, Dao has a history of mental health problems, including depression, anxiety and post-traumatic stress disorder, for which he has received treatment. A 2011 psychological evaluation of Dao concluded that he "lacked the foundation to navigate difficult situations, both inter-personally and in a complex profession.”
That evaluation also said Dao has struggled with “poor decision-making” and a “lack of awareness around his personality and relational issues.” The records said Dao had been previously cited by a hospital in the 2000s for “disruptive conduct” and was ordered to seek evaluation for “anger management” issues. In 2002, another doctor wrote that Dao sometimes “unilaterally chose to do his own thing.”
But another psychological evaluation administered in 2013 concluded that Dao “emotionally was free of debilitating anxiety, depression, or psychological turmoil to the extent that it would affect his ability to function in activities of daily living or manage the practice of medicine.”
