“Why am I here tonight?” Mateo asked. He took his glasses off and set them carefully on the gurney. “Because I don’t know why I can’t cry.” Looking at his hands, open in his lap, he considered each palm in turn, seemingly puzzled by its emptiness. Then his eyes came back up to mine, and his story began to slowly drain out, passively, by force of gravity.
He had been brought to the ER by his three brothers, who were surging about in the tiny waiting room down the hall; I was the psychiatrist summoned to evaluate him. My first impression, on stepping into the room, was that he seemed childlike — just 26 but appearing much younger, with smooth skin and rich brown eyes framed by thick black glasses; he looked as though he had lost his backpack, or perhaps was worried about his homework. And yet that impression lasted only an eyeblink.
Eight weeks earlier, he told me, his wife of a year — his pregnant bride — had been crushed and killed in their car. She was stolen from beside him late one night, as they drove in darkness on a country highway. They were returning from a weekend bed-and-breakfast getaway in Mendocino, when a white-panel van cut across their lane. Mateo jerked the wheel hard left, and their little car flipped into the median, finding a small tree stooped there that had been waiting quietly 50 years for this moment. They hung upside down for an hour, Mateo trapped beside his wife’s broken body, the young family swinging quietly in their seat belts — along with the little one too, deep within her, cooling slowly along with her, unsafe in her soft embrace.
He stared at the wall now, arms empty. Two months later, there was still visceral horror in his heart — but also a relentless dry isolation. As we talked, I learned this was a man whose inner self, his emotions, had been projecting out into the world — tears had come before, in his adult life, in many moments of joy as well as sadness — but this dimensionality was now reduced, his expressions flat and colorless. He seemed set aside, set apart in time, sighted in one direction only. When I asked about his plans, there was only nothingness. Mateo could not see even a few minutes into the future, which was invisible, impossible, a featureless white wall.
Crying is significant in psychiatry; our patients experience extreme emotions, and we work with the expression of these emotions. But the reason for tears is a mystery; pure emotional tears are not clearly present elsewhere in the great ape lineage, and with all the risks of revealing true feelings in complex social environments, the poor controllability of this emotional signal seems a handicap rather than an advantage. Yet value may lie in a signal remaining largely involuntary, and thus mostly true.
Every innovation in evolution is accidental at first. Our neurons are guided during brain development by a vast diversity of path-setting molecules as strong as thread-guides on a loom — tiny signposts that send a slowly growing bundle of nerve fibers, called axons, on to the next brain region, or turn it back if it has come too far. Mutation in genes governing any of these steps, redirecting axons from emotion-regulation regions of the brain, would be enough to bring into the world a new way of being human, with a new way of expressing feeling.
The new target here, for tears, would have been deep in the brainstem: the cells of the seventh cranial nerve, grandmaster of facial expressions but also of the lacrimal gland — the storehouse of tears. The lacrimal system likely evolved for flushing irritants from the eye, washing away particulate nuisances. With an almost-trivial rewiring, seventh-nerve control of tears would have become accessible by floods of emotion — with a tweaking of fibers already present, already projecting from emotion-control regions in the upper forebrain down to the brainstem parabrachial cells that regulate emotional changes in breathing (next-door neighbors of the seventh-nerve lacrimal cells) — and so finally wrenching, from within, the full cathartic, diaphragmatic contraction of the sob.
Mateo never did cry for his family — not that I saw, nor that he could ever tell me. In considering this, and the reasons we have for crying, it seemed to me that an odd unity links tears of sadness, when they happen, and the more mysterious tears of joy. Tears come when we feel hope and frailty together, as one. I managed to keep myself from writing this in the medical chart — and that Mateo had no hope left to cry for.
Mild improvements in material outcome that do not require a new model of self and circumstance — as with just making a bit more money in accord with known probabilities of the world — will not cause most people to cry. But when we do cry for joy — as when we feel the sudden warmth and promise of human connection, or when we see an unexpected depth of empathy in a young child — we seem to signal a flickering of hope, for the future of a vulnerable community, for humanity against the cold. We can cry at a wedding or a birth, seeing heartfelt aspiration but knowing deeply the fragility of life and love: I hope that the joy I see here will never die, I hope that the world will be kind enough to let this last forever, I hope that these feelings will survive — but I know very well they may not.
At the other, truly negative, pole of value, tears of sadness in adults also come not with mild losses from known risks but with sudden adverse personal realizations that must be addressed, and signaled (recruiting support from the self as well as from others) — like a shock of betrayal, when the hope we had for the future is shaken and our model of the world, our map of possible paths in life, must be redrawn. Large brains can contemplate many such possible actions and outcomes, ruminating and worrying, mapping out decision trees thickly ramified with possibilities projecting far into the future. But in situations where no positive outcome is possible, a passivity not only of body but also of mind can be adaptive — a deep discounting of hope, which would otherwise drain resources from our attentional and emotional budgets. Perhaps it is best to save the striving and the struggle, and to spare the trouble of tears when hope is gone.
Mateo was not suicidal, but among other symptoms of depression he had prominent hopelessness, an inability to look forward in time. Without hope for the future, Mateo could only look back. There was no point in signaling for help; his arms held nothing.
After talking it all over with Mateo and his brothers, we ended up sending him home with them — and with an appointment for follow-up care and medication — but not before I took the time to carry out an hour of predawn psychotherapy with him, right there in the ER, laying groundwork. When we can, we often steal the time to do this in psychiatry, almost instinctively, even during the besieged rush of an on-call shift. It can be hard to hold us back, as hard as it is to hold back surgeons from cutting to heal. We do this even knowing we will never see the patient again. I was discharging Mateo to the care of his family, and to outpatient treatment; in all likelihood our paths would never intersect again.
But that night, I had thought I could do something — not much, but something. And that matters — realizing at a place and moment you have been called to be whatever it is that humanity can be for a person. That is not nothing.
Karl Deisseroth is a Stanford professor of bioengineering and of psychiatry. He received the 2021 Albert Lasker Basic Medical Research Award for research on light-activated proteins, which led to optogenetics, a technology for studying the brain. This essay is adapted from Projections: A Story of Human Emotions. Copyright © 2021 by Karl Deisseroth. Published by Random House, an imprint and division of Penguin Random House LLC. All rights reserved.