You do not always want people to know what you are suffering from, and you might want to make sure that you are able to prevent others from knowing about your condition. There are a few reasons for why you might want to do this. The first, and simplest, is that it is not anyone else's business. The second is that people might look down on you for being in therapy or having a mental illness that has been diagnosed. So how do you keep it quiet?
The first way is to, if possible, schedule therapy after work by at least a half hour plus travel time. That way, if you are stuck late in work, you will be able to still make therapy. You do not need to leave at a specific time on the same day every week and make people suspicious. You want to do the same with your psychiatrist appointments. Doctor's appointments, every now and again, are fine, but when you are going every month or three months, people may start to get suspicious. You might even want to try and find a therapist or psychiatrist with evening hours. If you need to take medications during the day, keep it in something small that fits in your pocket (a small envelope works well here) and go to the bathroom to take your pills.
Finally, give your therapist and psychiatrist your cell phone number, but not your work number, and tell them when you are out at lunch and able to get to your phone. This way, you will not be getting calls at work where you are talking about appointments that might sound odd to a poorly-timed passer-by. Finally, check your insurance policies if they are through work, and make sure that they do not release anything to your employer. If they do, explore getting treatment outside of your insurance.