When I was a boy and there was a death in the family, the mirrors in our house would be covered with a sheet, as Jewish tradition dictated.

The “official” explanation of this custom, according to our rabbi, was that gazing at one’s reflection in a mirror is an act of vanity — and there is no place for vanity in a period of mourning. But my family had a different understanding of the practice: the mirrors were covered so that we would not see the face of the deceased instead of our own reflections.

As a psychiatrist, I think this bit of folk wisdom may see more deeply into the human soul than the theological teaching.

Recently, the theologian Bart Ehrman presented a very controversial argument, in his book How Jesus Became God. I have not read the book, but in an interview published in the Boston Globe (April 20, 2014), Ehrman argued that the belief in Jesus’s resurrection may have been founded on visual hallucinations among Jesus’s bereaved and grief-stricken disciples. Ehrman speculated that, “…the disciples had some kind of visionary experiences…and that these…led them to conclude that Jesus was still alive.”

Now, I am no position to support or refute Prof. Ehrman’s provocative hypothesis, but there is no question that after the death of a loved one (bereavement), visual hallucinations of the deceased are quite common. Sometimes, post-bereavement hallucinations may be part of a disordered grieving process, known variously as “pathological grief” or “complicated grief” — a condition my colleagues have been investigating for many years, and which had been proposed as a new diagnostic category in psychiatry’s diagnostic manual, the DSM-5. (Ultimately, a version of this syndrome was placed among disorders requiring “further study.”)

Though visual hallucinations usually are reported by a single individual, there are reports of “mass hallucinations” following some traumatic events; in such contexts, clinicians often speak of “traumatic grief.” A report from Singapore General Hospital noted that, following the massive tsunami tragedy in Thailand (2004), there were many accounts of “ghost sightings” among survivors and rescuers who had lost loved ones. Some would-be rescuers were so frightened by these perceptions that they ceased their efforts. There may well be a cultural or religious contribution to the Thai experience, since many Thais believe that spirits can be put to rest only by relatives at the scene of the disaster.

But “visionary experiences” also may be seen in normal or uncomplicated grief, following the death of a loved one, and appear to be common in many different cultures. In one Swedish study, researcher Agneta Grimby looked at the incidence of hallucinations in elderly widows and widowers, within the first year after the spouse’s death. She found that half of the subjects sometimes “felt the presence” of the deceased — an experience often termed an “illusion.” About one-third reported actually seeing, hearing and talking to the deceased.

Writing in Scientific American, psychiatrist Vaughn Bell speculated that, among these widows and widowers, it was “… as if their perception had yet to catch up with the knowledge of their beloved’s passing.” Since mourners or family members may be alarmed by these phenomena, it’s important for clinicians to understand that such transient hallucinations after bereavement are usually not signs of psychopathology. And, unless the hallucinations are accompanied by a persistent delusion — for example, “My dead spouse has come back to haunt me!” — they do not indicate psychosis.

In recent years, neuroscientists have investigated the underlying brain structures and functions that may account for hallucinations. However, we still don’t fully understand the neurobiology of these experiences, either in pathological states like schizophrenia, or in the context of normal grief.

Some clues may emerge from studying a condition called Charles Bonnet Syndrome (CBS), in which the afflicted person experiences vivid visual hallucinations, usually in the absence of delusions or serious psychological problems.

Often seen in older individuals, CBS may result from damage to the eye itself (e.g., macular degeneration) or to the nerve pathway connecting the eye a part of the brain called the visual cortex. This brain region may play some role in the “normal” hallucinations associated with bereavement — but evidence to date is lacking. (Imagine the difficulty of studying transient hallucinations in persons caught up in grieving the loss of a loved one!)

Some case reports theorize that in patients with pre-existing eye disease, the death of a spouse may increase the likelihood of Charles Bonnet Syndrome, suggesting that biological and psychological mechanisms are subtly interwoven.

Whatever the neurobiology of bereavement-related visual hallucinations, it seems plausible that these experiences often serve some kind of psychological function or need. Psychiatrist Dr. Jerome Schneck has theorized that bereavement-related hallucinations represent “… a compensatory effort to cope with the drastic sense of loss.” Similarly, neurologist Oliver Sacks has commented that “… hallucinations can have a positive and comforting role… seeing the face or hearing the voice of one’s deceased spouse, siblings, parents or child… may play an important part in the mourning process.”

On the one hand, there may be sound psychological reasons why Jewish tradition advises that mirrors be covered during the mourning period for a lost loved one. For some bereaved persons, visualizing the deceased while expecting to see one’s own reflection might be very distressing — even terrifying. On the other hand, such “visions of grief” may help some bereaved loved ones cope with an otherwise unbearable loss.

Suggested readings and references

Alroe CJ, McIntyre JN. Visual hallucinations. The Charles Bonnet syndrome and bereavement. Med J Aust. 1983 Dec 10-24;2(12):674-5.

Bell V: Ghost Stories: Visits from the Deceased. After a loved one dies, most people see ghosts. Scientific American. Dec 2, 2008.

Boksa P: On the neurobiology of hallucinations. J Psychiatry Neurosci 2009;34(4):260-2.

Grimby A: Bereavement among elderly people: grief reactions, post-bereavement hallucinations and quality of life. Acta Psychiatr Scand. 1993 Jan;87(1):72-80.

Ng B.Y. Grief revisited. Ann Acad Med Singapore 2005;34:352-5.

Sacks O: Seeing Things? Hearing Things? Many of Us Do. New York Times, Sunday Review, November 3, 2012.

Schneck JM: S. Weir Mitchell’s visual hallucinations as a grief reaction. Am J Psychiatry 1989;146:409.

Thanks to Dr. M. Katherine Shear and Dr. Sidney Zisook for their helpful references.