An abnormal craving to forget what is happening in his or her current existence: Some people who have been unemployed and are very depressed can suffer from a condition of letheomania and lapse into taking drugs to lessen their helplessness.

An obsessive desire for, craving for, or fascination with narcotics: In the article Mr. Atherton was reading, letheomania seemed to be common among some students had a very strong longing for opium, for example.