Why some grief never fades

Grief can bring waves of heartache, anger, or numbness—but for most people, those feelings gradually shift over time. For some, they don’t. The loss remains intense, persistent, and difficult to reconcile with daily life.

This condition, known as prolonged grief disorder (PGD), was added to the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5) in 2022. It describes a form of grief that doesn’t ease with time and interferes with a person’s ability to adapt to loss.

“There’s something interfering with their ability to finally say, ‘OK, I know it’s something I can’t do anything about. I have to accept this,’” says Katherine Shear, founder and director of the Center for Prolonged Grief at Columbia University, who has researched grief for decades.

Researchers are now beginning to understand why. Rather than reflecting overwhelming sadness alone, PGD may involve disruptions in the brain systems that govern attachment and reward, according to a 2026 review published in Trends in Neurosciences.

In people with prolonged grief, those systems may continue to signal that the lost loved one is still expected or “reachable,” creating a mismatch between memory and reality. Over time, that unresolved signal may make it harder for the brain to update and accept the loss.

“Because prolonged grief is a new kid on the block when it comes to diagnosis, in terms of understanding the neurobiology of it, we have a much smaller evidence base,” says Richard Bryant, a psychology professor at the University of New South Wales in Sydney, Australia, and co-author of the review.

Here’s what experts know about PGD’s impact on the brain and how it can be treated.

What is prolonged grief disorder?

PGD is a “chronic, intense, distressing reaction to loss,” that’s distinct from bereavement-related depression and anxiety, says Holly Prigerson, director of the Cornell Center for Research on End-of-Life Care at Cornell University.

Individuals remain “stuck” in their grief, she explains.

It’s typically marked by persistent yearning for the lost loved one, feeling emotionally numb or detached, a shaken identity or sense of self, and not accepting the reality of the loss, she adds.

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Many of these experiences are common in early grief, says Mary-Frances O’Connor, a psychology professor at the University of Arizona and author of The Grieving Brain. However, with acute grief, “there’s less yearning and more acceptance as time goes on,” she explains. “We’re not seeing change over time in people who have prolonged grief.”

Grief is considered PGD when symptoms last longer than 12 months.

Even though the PGD diagnostic criteria specify that symptoms are related to a person’s death, Bryant says, “There's no doubt that we see prolonged grief symptoms in all sorts of loss,” such as a relationship or deceased pet.

How prolonged grief affects the brain

The brain activity associated with PGD hasn’t been studied as extensively as depression or post-traumatic stress disorder, Bryant says.

What is known is that people with prolonged grief (like depression and PTSD) tend to ruminate and struggle to regulate emotions, he explains. Regions involved in reward and motivation—including the orbitofrontal cortex, striatum, and nucleus accumbens—appear to remain active in ways that suggest the brain is still expecting the presence of the lost loved one.

“What seems to be the case is that people with severe grief are still showing that reward expectation of their loved one, when they see a cute photo, for example,” O’Connor says.

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For those without PGD, a photo may activate the memory and emotion-related areas of the brain, but not the reward-expectation response “that they’re going to walk through the door again,” she explains.

Research published in 2020 and co-authored by Prigerson also found that PGD, compared to “normative grief,” involves different activity patterns in the amygdala and orbitofrontal cortex, which work together to process emotions and make reward-based decisions.

The study also suggests that the brain’s oxytocin signaling (the hormone involved in attachment, trust, and social connection) may work differently in people with PGD, Prigerson says, but researchers aren’t sure why.

People with PGD also show distinct activity in brain areas associated with memory, self-reflection, motivation, emotions, and cognitive processing, research suggests.

Why does it affect some more than others?

An estimated 4 percent of people develop PGD after a loss, Prigerson says. Researchers are still working to understand why, but certain patterns are emerging.

PGD is more common when a death was sudden or the result of violence, Prigerson explains.

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Personal circumstances also play a role. PGD risk is higher after the death of a child or spouse, or among people with a history of depression, who’ve experienced multiple deaths, who have a lack of social support, or who are emotionally dependent on the person who died, according to the American Psychiatric Association.

How prolonged grief impacts overall health

Prolonged grief disorder doesn’t just affect emotional well-being—it can have wide-ranging effects on physical health. It often occurs alongside conditions such as depression, anxiety, and post-traumatic stress disorder, and is linked to a higher risk of substance misuse.

Research suggests that PGD can disrupt blood pressure for years following a death and lead to a higher mortality risk within a decade. Shear adds that it can also impact the cardiovascular and immune systems.

Scientists are still working to understand why. One leading explanation is that prolonged grief keeps the body in a sustained stress response.

Under typical circumstances, the body’s stress systems—including the hypothalamic-pituitary-adrenal (HPA) axis—activate in response to a threat and then return to baseline. But in prolonged grief, that system may remain chronically engaged. Elevated levels of stress hormones like cortisol can, over time, strain the cardiovascular system, disrupt sleep, and interfere with immune function.

At the same time, persistent emotional distress may contribute to low-grade, chronic inflammation. This kind of inflammation doesn’t cause immediate symptoms, but over time it has been linked to a range of diseases, including heart disease, metabolic disorders, autoimmune conditions, and gastrointestinal issues, says O’Connor.

How to treat prolonged grief

Prolonged grief disorder does not typically respond to antidepressants, interpersonal psychotherapy, or other approaches used to treat depression, Prigerson says.

The mainstay treatment is Prolonged Grief Therapy, which involves 16 sessions and working through “healing milestones,” Shear says. These include understanding and accepting grief, imagining a promising future, strengthening relationships, narrating a story of the death, living reminders of the loss, and connecting with memories of the deceased.

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“The treatment really focuses on helping people accept the reality of the loss and restore their capacity for well-being, to thrive in their lives,” Shear explains.

Research suggests that about 70 percent of patients show improvement after the therapy.

The recognition of PGD as a formal diagnosis in the DSM-5 has also made it easier for the likelihood of detection, accurate diagnoses, and effective treatment (and insurance coverage) for people dealing with grief, Prigerson says. 

This is crucial, O’Connor says, as “prolonged grief is this disabling and unbending experience.” And, people need time and support to heal, Shear adds.