Hans Eysenck’s humor theory was actually based on very little but has had influence on many modern theorists such as Adler and Pavlov.
The last factor that He recognized was Psychoticism. Eysenck recognize that, there were some populations he had not including in his studies and he began to study people in mental institutions of England where an additional significant factor emerged, which he labeled psychoticism. Psychoticism means that the patient shows some traits commonly found among psychotics, and that they are more susceptible, given certain circumstances, to becoming psychotic. These traits include certain recklessness, disregard for common conventions, and a inappropriate emotional expression.