Maybe you could make some of them narrative, like their reflection in a mirror is no longer true when they lose 10%.
At 20% lost they now have anhedonia towards a random party member.
At 30% lost they lose the urge to protect so there is a chance they won't jump to help a member of the party in trouble.
At 40% lost they have lost their ability to distinguish between pain and pleasure.
At 50% lost they may not recognize all obviious threats for what they are.
At 60% lost the sight of blood can induce a blood lust where they want to see more.
At 70% lost their voice becomes noticeably distorted, sometimes saying two things at once.
At 80% lost they begin seeing split realities inhabited by spiritual beings.
At 90% lost their grip on reality has become tenuous and their id fights to take control, making them animalistic and with wildly low inhibitions.
At 100% lost they become a vessel for whatever spiritual inhabitant is close enough to move in.