Garrett was born in Beauparc, County Meath in Ireland on 17 March 1893.Lewis Spence. (2003). Encyclopedia of Occultism and Parapsychology. Kessinger Publishing. p. 366. Her parents committed suicide and Garrett went to live with her aunt.Jon Klimo. (1987). Channeling: Investigations on Receiving Information from Paranormal Sources. Jeremy P. Tarcher. p. 154. Garrett admitted she had a very unpleasant childhood and because of the anger of her aunt would "separate into a world of her own" where she could dissociate from her surroundings. She claimed to have developed psychic ability in her youth. She later married and claimed to hear voices and show symptoms of a dissociative identity disorder. Both Garrett and her husband believed she was on the "brink of madness", however, Garrett came to accept her condition and took up trance mediumship.Jenny Hazelgrove. (2000). Spiritualism and British Society Between the Wars. Manchester University Press. pp. 127–128. The psychologist Jan Ehrenwald wrote that Garrett's claims of psychic ability could easily be explained by "megalomania... ideas of grandeur" as she experienced mental dissociation, hallucinations and had an eccentric disposition from her childhood.John Booth. (1986). Psychic Paradoxes. Prometheus Books. p. 193.
