Gestalt Theory suggests, as I understand it, that we humans tend to perceive to some degree what we expect to perceive. For example, if I am thinking about the color red, there is a good chance I will notice instances of the color red in the world around me, more than if I had not been thinking of it.
Schizophrenics are known for having false ideas, and I wonder how many of these are bound up with a form of Gestalt. If a patient already thinks the FBI is tapping their phone, and a funny noise comes through the signal during a call, that will only corroborate their theory.
Even if the sound had to do with a cell signal issue, some storm somewhere, because the patient has this theory, their perceptions will fit that theory. They will attribute what they see, hear and experience to their expectations.
I feel that Gestalt Theory has good and bad aspects. On the one hand, we really do shape the way we take in the world around us, we have some authorship. On the other hand, we can become trapped in the world as we interpret it, bound to own own interpretations, which may be limiting at times, or false.
Keeping an open mind, and engaging in dialogue with others, would be good tools to combat the negative sides of Gestalt-style thinking.