I think the article makes some good observations. I think some people with psychosis operate between the different types on a variable basis. It's easier when a symptom first comes on to say it isn't real or that is is a benign coincidence. If the symptom/s persist it can erode the countermeasure beliefs and ideas and shift the perspective from "everything is still okay" to a "there is real danger" view. Other factors such as stress/anxiety level, amount of sleep, etc. can make the shift in perspective of psychotic symptoms change faster/slower.