Physical injury can destroy us, often inflicted by someone or something else, often just a tragic turn of events, sometimes fatal, sometimes you live.
Mental illness, we tear ourselves apart with only our minds. We lose a sense of knowing who we truly are, others feel like they don't know who we are anymore and desert us. Maybe, even if we normally like our own company, the isolation drives us mad. People forget about us, we are lost, trapped, sometimes we don't even know it, it's just the vaguest shadow of a thought, drifting like a ghost in the darkest alcoves of our minds.