I can tell you a major way of "fingering" BPD vs SOME (not all) of the other disorder are these three things:
- attachment issues (tend to attach to anyone that shows positive attention, and when in a relationship will do anything to make sure it does not end)
- abandonment issues (constantly afraid of relationships ending - for real or imagined reasons)
- black and white thinking - it's all or nothing, empty or full, everyone or nobody, everything or nothing, etc ... no middle ground

So yes BPD includes similarities to many illnesses but it has unique features as well. Those are the ones that should be watched for.