Research papers on the topic of the relationship between bereavment and hearing voices.
Grimby, A. (1998) Hallucinations following the loss of a spouse: Common and normal events among the elderly. Journal of Clinical Geropsychology, Vol 4(1), 65-7
In a widowhood intervention study of elderly Swedish citizens, ratings of grief reactions showed a high proportion of postbereavement hallucinations and illusions. Most common was the feeling that the deceased was present (illusion). Claiming to speak to, and to hear and see the dead spouse (hallucinations) was rather common. Very few had tactile hallucinations. Former marital harmony, loneliness, and severe crying are related to the incidence of hallucinations/illusions. Subjects had a dualistic attitude to the phenomena, as they were considered ridiculous sensations, but a pleasant and comforting rendezvous with the lost beloved one.
Olson PR, Suddeth JA, Peterson PJ, Egelhoff C. (1985) The hallucinations of widowhood. J Am Geriatr Soc. 1985 Aug; 33(8):543-7
Rees, WD (1971) The hallucinations of widowhood. British Medical Journal, 4, 37-41
Bettes B. A. & Walker, E. (1987) Positive and negative symptoms in psychotic and other psychiatrically disturbed children. Journal of Childhood Psychology and Psychiatry, 28, 555-568