There is some truth to this but it is also true that Police work has and can take it's toll on people. It is a high stress thankless job. When officers start to go into crisis, most Police Departments treat them as used dishrags rather than get them Critical Incident Stress Counselling. This stress can manifest itself in many different ways.
In my opinion, this is a crying f*cking shame, and it's one of the reasons I want this Drug War to stop.