A person having delusions and hallucinations does not questions them as he is fully convinced about them. In any case these are terms we use to classify a set of experiences that is not accessible to the average person. But hallucinations are simply contact with different orders of reality, that is all. So the question is how to differentiate between these different domains of reality given the complexity of creation. One simple way is the subjective and objective effect they have on us. If an experience, including vision brings calm, peace, inner joy, surrender to the Divine, then it implies some contact with the higher realms. But if it brings restlessness, ambition, increases vanity, arrogance, suspicion, anger, fear then it naturally implies contact with dark worlds.
Sometimes the effects are not immediate, especially when one is seeing things in the vital worlds which are full of deception. Therefore as a general rule seekers are advised not to let the mind indulge too much on visions and voices as they may distract if induged. At best they can be pointers showing us certain things, sometimes cautioning us, at times encouraging us on the way. Best is to stay focused on the main goals of yoga, that is discovery and growing union with the Divine and the ensuing change of consciousness and of human nature.
Hebephrenia is a different thing altogether with disjointed thought and emotional incongruity with other abnormal features.
Affectionately,
Alok Da
