From layman’s perspective subject suffer from Idol Mentality Disorder (IMD) seems like a normal bright highschool girl. From time to time IMD will cause a spike in emotional and physical activities as seen in subject H in Love Live! ep 1, Where subject H detemine to be a top idol, start dancing across the street avoiding car crash with supernatural agility and no care in the world whatsoever.
However, when further developed IMD will cause recklessness and denial in the subject which may result in subject dying or disability, as seen in Love Live ep 11, due to the alteration of subject mental state to not being able to think of anything but being top idol.
As demonstrated, IMD is a lethal disease which require further study to pinpoint the cause of all the symptom and developing a cure.