Grief is a natural reaction to the death of a loved one, but in cases of tragic or unexpected loss, that sadness can stretch out, affecting day-to-day functioning and reducing quality of life. Prolonged Grief Disorder (PGD) is a condition characterized by intense longing for the deceased, and by severe and persistent emotional pain. People who lose close family or friends to terrorism are at a particularly high risk of developing PGD.

In order to better understand grief reactions over time, researchers analyzed the effects of the 2011 terrorist attacks in Norway, in which a far-right Norwegian-born terrorist killed 8 people in a car bomb explosion in Oslo, then shot and killed 69 people on Utøya Island, most of whom were teenagers.

“The terror attack in 2011 was a huge national tragedy that affected all of us deeply,” says Dr Pål Kristensen at the Centre for Crisis Psychology at the University of Bergen in Norway. “Still, we needed to learn about the long-term mental health effects and how we could help those who were affected the most – the bereaved.”

Kristensen and his colleagues assessed grief in parents and siblings of those killed 18 months, 28 months, and 40 months after the attacks and recently published their results in Frontiers in Psychiatry. They found that grief trajectories could be classified into three different tracks: those who had a moderate level of grief 18 months after the attack, which then decreased by 28 months but then plateaued; those who had a high level of grief, which slowly decreased at both 28 and 40 months; and those who had a high level of grief which remained chronic. Nearly 80% of study participants experienced a high level of grief and either no recovery (13%) or a slow recovery (64%). Struggling with intrusive thoughts of the death seems to be a common factor that could explain the high number, as the combination of traumatic reactions and grief is known to delay recovery.

Other studies that examine grief trajectories after a disaster often find a “resilient” track, meaning that some people can adapt and bounce back after such tragedies. Kristensen and his colleagues, however, found no such group among the family members affected by the 2011 attacks, indicating the substantial effects of terrorism on mental health and grief reactions on close family members.

While the study had a fairly good response rate – out of the 208 family members that researchers reached out to, nearly 60% responded – knowledge is limited on how the non-responders are coping. As far as future research goes, Kristensen would like to see more longitudinal studies and more qualitative studies to learn more about how we can better tailor our interventions to the needs of the bereaved. “One size does not seem to fit all,” he says.”In fact, we have just finished a fourth wave of data collection where we are particularly interested in how those who struggle with prolonged grief have experienced treatment.”

In the meantime, it’s clear that support is needed for those who are suffering. “We need to reach out to the terror-bereaved to offer help,” says Kristensen, “both early after an attack, but particularly across time when the social support is reduced.” Recovery is a long road, but with a better understanding of how grief manifests over time, better care is possible.