Fregoli Delusion

Luis Fregoli's surname is also the name of a specific delusion in which the individual believes other people to be the same person. In the movie she finds that various people seem to be the same entity. Such as, the people in her apartment all being the same entity simultaneously.

When Gemma reveals herself to be the entity she says "Not you too, Gemma." By this stage she's thinking everyone is the entity.

However, if they are all the entity why the reference to the Fregoli delusion? Taken literally that would suggest that none are the entity and are infact different people.

At the end when she is on stage is she thinking the entire crowd is the entity? Is that why she looks so petrified? For instance, when she looks at her mother and she mouths "Smile."