This shows a brain like a tree and a sad person in its shadows.
Prolonged Grief Disorder is characterized by hyper-activity in the brain's reward and motivation centers, effectively keeping the individual in a state of chronic, unsatisfied craving for the deceased. Credit: Neuroscience News

Why Some Brains Are Biologically Unable to Process Loss

Summary: For most, the sharp pain of loss eventually transitions into a manageable memory. However, for approximately 5% of bereaved individuals, the “ache” never softens. This condition, formally recognized in 2018 as Prolonged Grief Disorder (PGD), is now being mapped by neurobiologists.

A new review reveals that PGD is characterized by a specific dysfunction in the brain’s reward-related networks. Rather than just an emotional processing error, brains with PGD appear to be “stuck” in a state of chronic craving and longing.

By identifying the neural signatures in regions like the nucleus accumbens and orbitofrontal cortex, researchers hope to differentiate this persistent state from depression and provide targeted treatments for those who cannot move forward.

Key Facts

  • The Reward Trap: PGD is linked to activity in brain regions involved in desire and motivation, suggesting the brain treats the memory of the deceased like a “reward” it is chronically craving.
  • The Six-Month Marker: While typical grief fluctuates, PGD is diagnosed when intense yearning and emotional pain persist for more than six months after the loss.
  • Distinct from Depression: While they share symptoms like rumination, PGD’s core neurobiology is tied more closely to the brain’s reward and motivation centers than classic major depressive disorder.
  • Identity Crisis: Individuals with PGD often feel as though a part of their own identity has died or that life has lost all inherent meaning.
  • Small Data, Big Need: Current research relies on small sample sizes; experts are calling for larger longitudinal studies to see how brain activity evolves as some people recover while others remain “stuck.”

Source: Cell Press

For most people, the intense ache that follows the death of a loved one eventually softens, and daily life resumes. But for some, the pain does not ease with time—a condition known as prolonged grief disorder (PGD). 

In a review publishing February 18 in the journal Trends in Neurosciences, researchers examine what is known about the neurobiology of PGD. The team highlights how disruptions in reward-related brain networks may help explain why grief persists in some individuals and illuminate how PGD differs from depression and anxiety.  

“Prolonged grief disorder is the new kid on the block in terms of psychiatric diagnoses,” says lead author Richard Bryant, a long-time trauma researcher of the University of New South Wales in Australia. Although grief has long been studied, PGD was only formally recognized in 2018. 

The core experience of PGD resembles typical grief, including intense yearning, longing, and emotional pain. But for about one in every 20 bereaved people, the pain persists and lasts beyond six months after the loss. They may feel that life has lost its meaning, part of their identity has disappeared, or they cannot accept death, even though they know it has occurred. 

“It’s not that it’s a different type of grief,” says Bryant. “It’s just more that the person is stuck in the grief.” 

To understand why some people remain stuck, Bryant and his colleagues turned to the neurobiology of prolonged grief—a field that is still in its infancy and often relies on research with small sample sizes and varying experimental designs, complicating comparisons across studies. 

Much of the research in the field comes from neuroimaging studies, which ask bereaved participants to recall or view reminders of the deceased during brain scans. Across these studies, PGD has been repeatedly linked to changes in reward-related brain circuits.

These regions include the nucleus accumbens and orbitofrontal cortex, which are involved in desire and motivation, as well as the amygdala and insula, which play roles in emotion processing. 

“It sort of gelled with this notion that grief is characterized by a craving or a longing for the deceased,” says Bryant.  

Some of the neural patterns observed are not unique to prolonged grief. Similar changes appear in depression and post-traumatic stress disorder. Given that these conditions share the same traits such as rumination and emotional distress, “it would be very strange if we didn’t get that overlap,” says Bryant. 

However, this poses a challenge for researchers to tease apart which brain changes are specific to PGD and whether the observed brain differences cause prolonged grief or result from it. 

Looking ahead, Bryant emphasizes the need to work with larger groups of bereaved individuals over time to reveal how grief-related brain activity changes as some people recover while others do not. 

“I hope to raise awareness,” says Bryant. “To actually deal with prolonged grief, we need to recognize it as a disorder. We do have treatments that can address it, but we can’t do that if we can’t identify these people.” 

Funding: This work was supported by National Health and Medical Research. 

Key Questions Answered:

Q: Is prolonged grief just “extreme” sadness?

A: Science suggests it’s more like a biological “stuck” state. While sadness is part of it, the brain imaging shows high activity in reward centers, meaning the brain is essentially “addicted” to the longing for the person who is gone, preventing the natural transition into acceptance.

Q: Why does the reward center light up during grief?

A: It sounds counterintuitive, but the nucleus accumbens handles longing and desire. In PGD, the brain keeps trying to “find” the deceased loved one through memory, triggering a craving response that never finds satisfaction, keeping the person in a loop of intense yearning.

Q: Can Prolonged Grief Disorder be treated?

A: Yes, but first it must be identified. Recognizing PGD as a distinct disorder rather than “just depression” allows clinicians to use specific therapies designed to help the brain’s motivation networks re-engage with the present world instead of the past.

Editorial Notes:

  • This article was edited by a Neuroscience News editor.
  • Journal paper reviewed in full.
  • Additional context added by our staff.

About this grief and neuroscience research news

Author: Julia Grimmett
Source: Cell Press
Contact: Julia Grimmett – Cell Press
Image: The image is credited to Neuroscience News

Original Research: The findings will appear in Trends in Neuroscience

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