I mentioned it my thoughts in another post. It should be mandatory for officers to seek mental health during and after serving. They see more trauma than most, and their training to make quick decisions can easily hinder their daily thinking process. It really takes the right kind of person for the job, but at the same time, their job should not be on the line for a mental illness that their job created. So long as they are seeking treatment and staying with it, definitely should not be an issue.
On the other hand, there is often corruption in police departments, which can easily turn someone away from wanting that job. The thought that you could be doing your best and what you were trained to do, and then all of a sudden an "incident" or "fatal incident" happens, because you caught on to the corruption and someone doesn't want their secret out...