How can mental health issues have an impact on a persons career?

Mental health can effect you but also not effect you. If your mental illness is affecting your ability to do things, such as concentrating or communicating effectively, you’re probably aware of it. So it could be ether way. The effect on it can be having a social relationship. Many mental people have trouble interaction with peers so that 1 effect.

Being mentally healthy is so, so important! I don't think a lot of people realize this, but having depression or feeling mentally drained can affect the way you do your work. You might not be as focused as you should be and make errors. I believe it is important to take breaks when you are at your lowest. Of course don't miss too much work, because you'll just get fired. But having a clear, positive mind really makes a difference.