Grief, while often understood as a non-linear process, can become a never-ending experience for a small percentage of individuals.

An estimated 10 percent of those who have lost a loved one experience Prolonged Grief Disorder (PGD), a psychiatric condition defined by very difficult feelings such as sadness or guilt that persist for more than six months.

PGD was formally classified by the World Health Organisation in 2018 and is characterized by elevated levels of bereavement-related distress.

According to some reports, individuals with PGD frequently dwell on the deceased, struggle to accept the death, may experience suicidal thoughts, and find it difficult to resume everyday activities.

They might feel that life has lost its meaning, or that they have lost a part of their identity, and despite knowing the death has occurred, they cannot truly accept it.

People who have experienced a traumatic or sudden loss are more susceptible to PGD, though it does not affect all such individuals, a phenomenon that has long puzzled scientists.

A new review, published in the medical journal Trends in Neurosciences, sheds light on the neurobiology of PGD and aims to understand why it persists in some individuals.

Researchers from the University of New South Wales in Australia suggest that PGD exhibits brain patterns similar to those observed in patients with depression and anxiety, along with activity in systems associated with reward and attachment.

This could imply that affected individuals are experiencing a deep psychological 'craving' for the presence of their lost loved one, making it challenging to move forward effectively.

Lead author Richard Bryant explained that Prolonged Grief Disorder is a relatively new psychiatric diagnosis.

He clarified, "It's not that it's a different type of grief. It's just more that the person is stuck in the grief."

He added that this aligns with the notion that grief is often characterized by a craving or longing for the deceased.

Bryant's team synthesized findings from previous studies on PGD, primarily functional MRI (fMRI) brain scans, which measure blood flow changes when individuals view photos of the deceased or reflect on their loss, as well as grief provocation tasks.

Reports indicate that these studies consistently link PGD to alterations in reward-related brain circuits.

Specifically, regions like the nucleus accumbens and orbitofrontal cortex, crucial for desire and motivation, show changes, as do the amygdala and insula, which are involved in emotion processing.

The observed brain patterns also overlap with those seen in depression and post-traumatic stress disorder, conditions that share traits such as rumination and emotional distress with PGD. Bryant noted, "It would be very strange if we didn't get that overlap."

He expressed hope to broaden his research by working with larger groups of bereaved individuals to monitor how their brain activity evolves as they navigate or become stuck in grief.

Also, Bryant aims to raise awareness about PGD. He emphasized, "To actually deal with prolonged grief, we need to recognise it as a disorder."

He concluded by stating that treatments are available, but their application is contingent on the ability to identify those suffering from the disorder.