When someone is struggling, especially with trauma that results in ptsd for example, if they can talk about the episodes/events they were traumatized they can pinpoint what about that event affected them and work through the affects of a traumatic event or episode. If a person experienced a lot of traumas since early childhood they may be so traumatized they don't even remember it in an espisodic way.

A person can be so sensitive as TheUrOther describes they can barely interact vocally normally. Some try therapy but end up disassociating, those patents are very hard to treat for example.