No human contact

there are some people who lived in the woods for decades and they can still interact normally even if they have some speech retardation of some sort because of not using it a lot.

Why would they go insane? Many people have lived by themselves for most of their lives and probably have more experience and general knowledge than most of the community. What I think drives people crazy is when they are alone and they do not want to be, but if they choose to live alone it is a very easy lifestyle to adapt to.

Man is a social creature and he can only progress when he comes into contact with his fellow beings and uses them for making his life fulfilling. However there are certain people who have cut contacts with the human race and are living a life of total solitude.It is very hard to come across such people because they live in very remote locations which are untouched by man Such people are known as hermits.By doing years of deep meditation they have conquered all the aspects of life and can be on their own without meeting a single human or going insane.They are the proverbia needle in the haystack and it is very difficult to come across any of them.

I think I can.

Do you mean contact by communicate? I don't think so. Human are individual and social as well. As social beings, human beings need to interact with others. I think we can't live alone. We need others to communicate, and help each other. We can't do anything by our self. I can't believe in this age there is people could live alone except if they are crazy.