Anaclitism - Diaper fetishes are sometimes mentioned as an example of anaclitism, a desire for things one was exposed to in infancy. Anaclitism is a more general term in one way, as the objects don't necessarily have to be infantile, just things that one would have been exposed to during infancy. However, it is more narrow in another way: It implies that the conditions started in infancy. While anaclitism's definition fit into Freud's theories well, it hasn't been developed or supported empirically.
Adult Babies and Diaper Girls
A diaper lover is different from an AB because they are fundamentally focused around the wearing of a Diaper or Nappy. For a Diapers Lover, it is all about the feel of the diaper and usually its use, that is, the intended use of a diaper. DLs tend to be more sexually motivated then ABs and usually integrate Diaper Play into their general sex life, like prolonged bondage or watersports.