I've known families who homeschooled. It was my observation that in some cases one of the motivating factors was a means of restricting the child's exposure to the larger world. This seemed to be more prevalent among families who also identified religious beliefs as playing a crucial role in their decision to educate their children at home. It stands to reason that a restrictive, controlling, or possibly punitive environment could contribute to mental health difficulties although this may have more to do with parental attitudes than the medium itself.

I've known of other families who home-schooled as a means of expanding their child's involvement with the world. Different concerns informed their decision such as respect for child-led learning or a desire to travel and interact with the larger world outside of the traditional classroom setting.