Maniae
In Ancient Greek mythology, the Maniae or Maniai are the spirit or spirits of madness. Later poets also used the singular form, considering her as an independent personification of insanity, madness, and frenzied delusion, symbolizing various forms of mental disturbance such as hysteria, delirium, delusion, obsession, and possession. She or They operate closely with Lyssa, the spirit of rage and rabies, and, like Lyssa, are generally presumed to be daughters of Nyx. The Maniae are also associated with the Erinyes, the three fearsome goddesses of vengeance.
They are sometimes said—perhaps in jest, or as a metaphor for love’s often cruel and maddening nature—to have been the nurses of the god Eros.
Mania is mentioned in Iliad by Homer, as one of Ares' companions in war, alongside Lyssa and Penthos.
Etymology
The Greek noun μανία means “madness” or “going astray,” but also “inspiration” and “enthusiasm.” However, poets, when referring to the divine personification, invariably used the term with a negative connotation. They were invoked in ancient Greek rituals to avert or control madness, highlighting their dual role as both the causes and potential remedies for insanity.
Roman counterpart
Her Roman counterpart was a more prominent and independent figure. In Etruscan mythology and Roman mythology, Mania, also spelled Manea, was a goddess of the dead, spirits, and chaos. She was said to be the mother of ghosts, the undead, and other spirits of the night, as well as the Lares and the Manes. Together with Mantus, she ruled the underworld.
Mythology
Pausanias writes that on the road from Megalopolis to Messene there was a sanctuary, which, according to local citizens, was devoted to goddesses called Maniae, and that its surrounding district was also called Maniae. His local sources told him that it was there that madness overtook Orestes, hence Pausanias's view that these Maniae were the vengeful Furies or Erinyes or Eumenides.