Cat Herder,
The decision to tell your employer, and/or go on stress leave all depends on that employer. In my experience, employers have to be more concerned about their bottom line than your personal situation. They may care about you personally, but they have a business to run, and a responsibility to put the business first.
If there is any way you can reduce your stress - at work and outside of work - to get back on track with management's expectations, that would probably be better... Once they know you have PTSD, they will always see that as a liability, and you won't be able to un-do that.
In making the decision to tell your employer (or not) you might consider the following:
1. How long have you worked there, and what does your long term performance record look like?
2. What has happened with other employees who went on leave - were they able to return successfully?
3. What would be your goal in telling them and/or going on leave? Is there a different way to achieve that same goal while continuing to work?
4. What would you do while on leave, or after telling them in order to improve your performance? What's your plan? If you're doing this just to get them off your back, the result may not be very good - again because they have a business to run, regardless to how compassionate they may be to your situation. If you communicate your plan to get some therapy, medication, support, coaching or other constructive activities, it will hopefully make your employer feel that you care about their business and you are doing all you can to get up to par.
I wish you the best in getting through this situation - it takes courage to work through it rather than running away or letting emotions run your decision making process. :ninja:
-Erica