I was fascinated by an article that I read over the weekend that illustrates how in some patients, suffering from depression, that there was areas in the brain experiencing inflammation. Effectively, white blood cells were making their way to certain areas of the brain and causing inflammation. What was interesting is that some researchers believe that the feelings of depression are what are causing the inflammation and not the other way around. Meaning, you can worry yourself to the point where you body actually thinks that the brain is in trouble and sends white blood cells to save the day. This causes inflammation and makes symptoms worse and often times will even prevent certain medications from functioning.
Your brain can actually get into trouble from you worrying too much. That is hilarious, right up until the point that it happens to you. Then it really sucks. So the best prevention is to really focus on spending time away from worrying and stressing about things and do brain reinforcing and positive activities that send better signals to your body that your brain is active and healthy.
There is probably some truth to the concept that people that are more mindful and do daily restorative things are more likely to have a healthy functioning mental state and as a result a better functioning body and soul.