i think not necessarily. it depends on your past. i personally think that not having emotions could be a coping mechanism. You learn to not let yourself feel that deeply about anything, especially if you have had a traumatic history because it hurts too much to feel.

that being said, i also think that it could be a trait of another disorder, possibly anything from ADD (overlooking the proper response), to autism (not reacting appropriately and/or not noticing social cues), to things such as personality disorders. I think if you are worried about it, it wouldnt hurt to get checked out by a doc.