" Comfort and consistent tactile experiences help the baby develop a sense of its body as a safe and consistent boundary. If the baby is not held and comforted, or is frequently dropped, or handled roughly, or neglected or abused—painful, disruptive experiences British pediatrician and psychoanalyst Donald Winnicott called impingements—the child will not grow to feel like a whole entity, sheltered and contained by her skin. The failure to master this first important developmental task makes it difficult to differentiate between self and others, inner and outer, thought and action, fantasy and reality. Later, the child or adult may use cutting to work out these conflicts in a concrete, literal way on the body, reverting back to the most primitive means of psychic organization the knows to test her own reality. "

― Marilee Strong , A Bright Red Scream: Self-Mutilation and the Language of Pain