The definitions is incomplet, that would fit in a range of disorders.
Schizotypal , avoidant and Schizoid personality disorders interefeer in interpersonal relationships.
i think it's for a medic to tell if you have some of this disorder, i find it quite hard to see the diference!
you may find a better explation at
http://en.wikipedia.org/wiki/Schizotypal_personality_disorder
SA may be a comorbity, what means its related with the personality disorder.
i just know that AvPD (avoidant ) almost always comes with a enormous deal of SA...