American neurologists have described new cases of a rare mental disorder - Witzelsucht, or an uncontrollable urge to joke. Scientists have noted the independent nature of the defeat of laughter and sense of humor, as well as the variety of injuries that lead to unusual symptoms. The study is featured in The Journal of Neuropsychiatry and Clinical Neurosciences and is briefly reported by Discover.
Scientists tell the case histories of two patients with different etiology and course of development of Witzelsucht. The first is a 69-year-old man who has been tempted to joke for five years. This property ultimately displeased his wife: the patient often woke her up at night to tell a new joke. As a result, in order not to bother his spouse, he began to write them down in a separate notebook, which he brought to the doctors. Doctors linked the disorder to a recent stroke that damaged the left caudate nucleus. However, another reason could be subarachnoid hemorrhage, which damaged the right side of the frontal lobe.
The second patient is a 57-year-old man who, over the years, has become a joker. At the same time, he became more and more relaxed, behaved more and more indecently. As a result, he started joking almost non-stop and laughing at his own jokes. Someone else's humor seemed to him absolutely not funny. In the future, the man's mental state continued to deteriorate: he developed symptoms of Parkinson's disease, and a few years later he died. Autopsy indicated Pick's disease (destruction and atrophy of the cerebral cortex).
The authors of the study note that in the human psyche, laughter functions autonomously from the sense of humor: unlike uncontrolled laughter in any situation (a common symptom), with Witzelsucht, laughter is adequate: patients actually find their jokes funny.
Previously, the cause of this disorder was thought to be damage to the orbitofrontal region of the right side of the brain. Scientists note that disturbances in the functioning of neural connections between the frontal lobe and subcortical structures of the brain may also play an important role in this.