Definition: a sudden and overwhelming urge to interrupt a conversation with a soliloquy directed toward and expressing concern for someone who is not present, namely a plumber named Joe.
Etiology: Poorly understood. Possibly related to Tourret's Syndrome. Often associated with feelings of extreme desperation. Widely considered to be a side-effect of selling one's soul to the devil. CGP is recognized as a component of McMaverick Syndrome, a rare but complex and pernicious disorder characterized by wildly erratic behavior consistent with being a cranky sore-head.
Signs/Symptoms: Sudden onset of the appearance of a great concern for one particular individual in the plumbing profession. Frequent verbal reassurance is given and promises made to this person, delivered as if the person were actually there in the room. Frightening pathology as attacks indicate irreversibility of disease. Once this stage is reached symptoms increase with alarming severity and frequency.
Treatment: no known treatment.