A medical professional recently told me about a strange and little known
malady. Somehow, it seemed appropriate to forward the information here.
I did not make this up. Honest.

witzelsucht (vitsel-zoocht) [Ger.]

A mental condition characteristic of frontal lobe lesions and marked by
the making of poor jokes and puns and the telling of pointless stories, at
which the patient himself is intensely amused.

From Dorlands Illustrated Medical Dictionary, 26th edition.