I would like to know when you as an amateur/ordinary person can begin to suspect that a woman which have a pattern of being emotionally unstable, when that crosses over to be a full borderline diagnosis?

For me those things are always very difficult to know, and although Wikipedia DSM IV page has the so called criterias, it is still difficult to know, so I am wondering a little about that.

When can you really suspect that a woman suffers from borderline diagnosis?