Physicians in the United States have a significantly higher suicide rate than the general population
The combined results of 25 studies suggest that the suicide rate among male doctors is 40 percent higher than that among men in general, whereas the rate among female doctors is 130 percent higher than that among women in general.In the general populations, females are more likely to attempt suicide, but males are more likely to succeed since they generally choose more effective methods (e.g. shooting themselves in the head). A significant reason for the increase is that physicians, and female physicians in particular, are much more likely to be successful when they attempt suicide, probably because they have access to drugs and knowledge about how to use them more effectively.
As the NEJM Perspective the quote comes from points out, physicians with mental illnesses such as depression or substance abuse problems are probably reluctant to seek help for fear of jeopardizing their licensure, which is, of course, crazy.