In psychology, multiplicity usually indicates abuse. This is a fallacy; it does not take abuse even to create trauma-induced multiplicity -- what is trauma to a child may not be considered abuse even by the strictest of legal definitions, nor does it need to be against the child, nor does it need to be something done by someone in a diliberate manner to bring harm to any persons. On the other end of this, it's ill advised to dismiss abuse if it comes up amongst the things that a multiple has experienced.
Traumas that don't fall under abuse are covered elsewhere: Illness and accidents, natural disasters, terrorism, wartime, inconsistent care and witnessing abuse would fall under the broader category of trauma without falling under the category of abuse. We reserve this area for acts done directly to a child, some of which are not necessarily conscious, but most of which are deliberate in some way or other. In cases of abuse, it's relatively simple to point to someone whose fault it is, someone who perpetrated the abuse.
Neglect can fall both under deliberate with fault, or under general without fault. It's difficult to categorize neglect because it's "trauma where no one does anything in particular, and too often does nothing at all." It's discussed elsewhere due to this conflict.