Which of the dsm iv classifications of personality disorders is characterized by social and interpersonal deficits, and eccentric behaviors that inhibit the development of close relationships?

I believe the answer is: schizotypal

People with schizotypal disorder tend to experience excessive anxiety and paranoia, which led to social and interpersonal deficits.

It is also very common for people with this type of disorder to develop unconventional belief that might perceived as nonsensical by most normal people.