Margaret Mahler's theories of child development include the notion of Object Constancy. This is believed to develop under the age of two, hence prior to laying down long term memory.
Given the, potential, severity of problems associated with a damaged Object Constancy.
Given that many modes of psychological therapy involve an exploration of a person's psyche, and this tends to be within the scope of ages of remembered experience.
How is it possible to provide help for people with damaged Object Constancy, if the damage is believed to be preverbal?
[I am not suggesting all experiences are remembered, it is just unusual for people to discuss their experiences at the ages of birth to two, as there is, usually, absolutely no memory. Any discussion, usually involves information the patient has obtained from others, rather than experience.].