Psycho student refers to a group of students whom mentality is not fully developed; they don't know what are the right ways to react other people's actions. For example, a small group of students are talking too loud in a class, the psycho students wouldn't tell them directly to shut up, they prefer to use they own ways to deliver the message, such as they would cough, making funny sound to "tell" them to shut up.

When you eat dirt for the first time and leave your family to build a shack in the woods