Yearning predicts subgenual anterior cingulate activity in bereaved individuals

Abstract

Complicated grief, or persistent complex bereavement disorder, is a condition that affects approximately 10% of bereaved individuals and is marked by intense longing and yearning for the deceased. Little is known about the neurocognitive mechanisms contributing to this syndrome, but previous research suggests that reward pathways in the brain may play a role. Twenty-five older adults were categorized based on grief severity into one of three groups: complicated grief (CG), non-complicated grief (NCG) and non-bereaved married controls (NB). Neural activation was examined using fMRI while participants viewed a countdown on the screen (anticipation) followed by a photo of their (living or deceased) spouse. There was no significantly differential activation between the three groups for the spouse v. stranger photo contrast, nor for anticipation period v. spouse photo. Post-hoc analyses were conducted using self-reported yearning scores as a regressor across all bereaved participants, which revealed that greater symptoms of yearning predicted greater activation in the subgenual anterior cingulate cortex (sgACC). Given the small sample size, the results should be considered preliminary and in need of replication, but may suggest a more nuanced, transdiagnostic role of the sgACC. This region of the brain has been previously linked to depression and suggests that symptoms of yearning may present an opportune place to intervene to improve outcomes in CG.

The neurobiological reward system in Prolonged Grief Disorder (PGD): A systematic review

“…The authors proposed that sgACC activation is associated with a stressful grief experience, though PGD was not assessed. A later study by McConnell et al (2018) observed no significant differences in sgACC activation between those with PGD and those without. However, in a symptomspecific analysis of all bereaved participants, the authors found that yearning (as assessed by the yearning item in the ICG) was associated with activation in the sgACC, independent of other ICG items or total score (O'Connor et al 2018).…”

“…The NAc co-activated with areas associated with pain, such as the insula and periaqueductal grey, prompting O' Connor et al (2008) to suggest that "craving" for the deceased was experienced as an affliction, as in addiction. A subsequent study attempted to replicate this finding with an older sample, but found no significant difference in NAc activation between PGD and non-PGD groups (McConnell et al 2018). The authors suggested this null finding may have been due to a small sample size or to the age of the subjects (the average age was 71 years, as opposed to 44 years in their 2008 paper), citing non-human animal research that shows a decline in certain NAc activity with advancing age (Ruegsegger et al 2017).…”

“…These findings suggested that reminders of the deceased are processed by the reward system, and that the protracted yearning characteristic of PGD may reflect a combination of craving (commonly observed in addiction disorders) and rumination (commonly observed in MDD and anxiety disorders). (McConnell et al 2018). What did emerge, however, was evidence for PGD-associated activity in the amygdala and OFC; likely in the PCC, rACC, sgACC, and basal ganglia overall; and possibly in the insula.…”

“…Such diversity in study design makes it difficult to interpret the variation in findings observed. It is also important to note that 5 of the 7 fMRI studies of populations with PGD involved members of one research group (O'Connor et al 2008Arizmendi 2018, Arizmendi 2016, McConnell 2018, O'Connor and Arizmendi 2015. This reflects the relatively primitive stage of the field and punctuates how important it is for researchers to attempt to replicate findings and pursue research in this area.…”

Neuroendocrine mechanisms of grief and bereavement: A systematic review and implications for future interventions

“…This under‐stimulation could in the long run even be related to the symptoms of PGD/PCBD. Additionally, studies investigating neural correlates of social loss indicate grief‐related altered activation in brain areas such as the NAcc 112 and the ACC, 113 which are associated with the reward‐system and high OT receptor densities. However, endogenous OT mechanisms in the central nervous system cannot be measured in the human living brain so far, which limits the possibilities to test for direct involvement of OT in the grieving process.…”