There are a lot of fissures in the psyche of any given person that will turn into full-blown cracks if that person isn’t given a certain degree of emotional reinforcement from others.
People who are highly gifted tend to absent themselves from others, since they need to be alone to develop their gifts.
The downside, of course, is that they receive a lot less validation and comfort from others. This may have the consequence that any hairline fractures that there might be in their psyches bloom into full-blown psychopathologies.
That said, loners are, at most, only marginally more prone than others to psychopathology. What’s going on is that, being loners, they can ‘let their hair down’ and let all of their eccentricities come out, whereas people people don’t have that option.
But people people have loads of psychopathologies, as you find out whenever you get to know one in an environment where they don’t have to keep the mask of sanity painted on.