Acedia: Its Evolution from Deadly Sin to Psychiatric Syndrome

Iohannes Cassianus, more commonly known as John Cassian, wrote his treatise De Institutis Coenobiorum et de Octo Principalium Vitiorum Remediis Libri XII around the beginning of the fifth century A.D. This work is important because it introduced certain Eastern ideas into Western thought. Some of these ideas are of considerable psychiatric interest.