What is the Ni-Ti loop? Ni-Fi? - Confessions of a Myers Briggs-aholic
Again...
"They may become an exaggerated version of themselves, overwhelmingly outgoing or extremely withdrawn. They will also seem to miss a huge part of their normal, healthy personality; whatever behavior or thought processes their auxiliary function would normally govern. However, these differ for each type depending on the function being skipped."
So far anyway, nobody is contradicting SW's theory.
It's necessary to also mention, with regard to the INFJ in particular, that this type is not automatically social or sociable simply because Fe is the auxiliary function. With Ni as the dominant function, Fe becomes a very broadly - applied or generalized - theory of social values.
If the INFJ is not in a loop, then the theory will be applied, not just generalized. The INFJ will be actively engaged in trying to change the world in accordance with a vision. Examples of that (not speaking for any particular INFJ) would be fighting for human rights on a global scale and the transforming of society in accordance with a personal vision of a better world. Tertiary Ti, although less developed, attempts to add a logical backdrop in the form of philosophy or rationally persuasive argument (a treatise, for instance).
If the INFJ loses hope and confidence that the vision will be realized, then withdrawal and a sense of hopelessness will be the result. I'm not agreeing with SW that this would result in a Schizoidal personality or any personality disorder at all. But depression is a given.