I wonder what the racial and gender make-up of such people is. The author mentions that,
form paraphilias take differs not merely among individuals, but from one culture and historical period to another. When Richard von Krafft-Ebing was writing about paraphilias in 19th-century Vienna, he described men who were sexually obsessed with handkerchiefs. That paraphilia has largely disappeared. Yet many others have emerged.
It is estimated that up to 10% of Western European population was mentally ill in the Middle Ages. Ill as in "raging mad". Cities were filled with men and women gripped by "devils", paraplegics and worse with a large number of them being somehow psychosomatically afflicted. That is one of the reasons so many "miracles" of healing by touch or holy water occurred -- there was little physically wrong with many of the victims. Similarly, in 19th Century upper-class women would regularly faint on all sorts of occasions, quite honestly and unpretentiously pass out from embarassment. As time went out and women were seen as less fragile these spells disappeared quite completely from the society.
Our times see the same play performed all over, except now it is attention-deficit or anorexia. I am not saying these are not deseases, just that the article thoughtfully points out that for some reason their study is rarely subjected to the same rigors illnesses with more obvious physical causes are.