Can you tell me if a person has a schizoid personality disorder, would they be interested in playing sports, like boxing?

Why do you ask?: There's little point in making a diagnosis of "personality disorder" since there's no magic pill to cure it, and the real question is, "What can I do to help myself / this person be happier and more fulfilled?" A fair number of folks are loners, withdrawn, don't communicate well, prefer low-maintenance relationships. Boxing's a sport where you train alone & would be a good one for such folks.

Not impossible: Like Dr. Friedlander answered, boxing allows for quite a bit of alone time. A team sport is very unlikely to be a good match but it is not necessary to predict - rather you can find out by trying it. Whose idea is boxing? If it's the person themself, it may be good. If someone else wants to suggest it, less good. Don't push past a "No, thanks". God luck!

Not likely: The hallmark of the schizoid personality disorder is an indifference to interpersonal relationships. In plain English, these folks prefer to be alone much of the time, and are not lonely because of it.