Answer:
Borderline
Step-by-step explanation:
Borderline disorder maybe seen in some quarters as a form of mental disorder which is often characterized by a very strong mental instability, that is a very quick swing in behavior or character towards a particular person or phenomenon. Borderline disorder are usually chronic and has no established permanent cure. Like described in the question above, patients suffer from very abrupt change in feeling which is strange and hence, it's relation or inclination towards mental disorder or ailment.