Elsevier

NeuroImage

Volume 42, Issue 2, 15 August 2008, Pages 969-972
NeuroImage

Craving love? Enduring grief activates brain's reward center

https://doi.org/10.1016/j.neuroimage.2008.04.256Get rights and content

Abstract

Complicated Grief (CG) occurs when an individual experiences prolonged, unabated grief. The neural mechanisms distinguishing CG from Noncomplicated Grief (NCG) are unclear, but hypothesized mechanisms include both pain-related activity (related to the social pain of loss) and reward-related activity (related to attachment behavior). Bereaved women (11 CG, 12 NCG) participated in an event-related functional magnetic resonance imaging scan, during grief elicitation with idiographic stimuli. Analyses revealed that whereas both CG and NCG participants showed pain-related neural activity in response to reminders of the deceased, only those with CG showed reward-related activity in the nucleus accumbens (NA). This NA cluster was positively correlated with self-reported yearning, but not with time since death, participant age, or positive/negative affect. This study supports the hypothesis that attachment activates reward pathways. For those with CG, reminders of the deceased still activate neural reward activity, which may interfere with adapting to the loss in the present.

Introduction

Grief is one of life's most painful experiences. When suffering the loss of a loved one, one can feel as if the attendant sadness and longing will last indefinitely. Although successful adaptation to the loss is the most frequent response (Bonnano et al., 2002), grief does not abate in a substantial minority; rather, it develops into Complicated Grief (CG) (Ott et al., 2007). CG, previously known as chronic, pathological or traumatic grief, includes debilitating recurrent pangs of painful emotions, with intense yearning, longing and searching for the deceased, and preoccupation with thoughts of the loved one. This syndrome has now been defined by an empirically-derived set of criteria (Boelen and van den Bout, 2005) and is being considered for inclusion in the DSM-V.

The neurocognitive mechanisms involved in CG are currently unknown. Some have hypothesized that attachment may activate reward pathways and that this neural response may have addiction-like properties (Insel, 2003, Panksepp et al., 2002). We hypothesize that a major neurocognitive difference between CG and Noncomplicated Grief (NCG) is that reminders of the deceased may still activate neural rewards for those with CG. This reward activation may interfere with adapting to the loss in the present. Supporting this idea are subjective reports from CG patients indicating pleasurable reveries about the lost love (during which the reality of the loss is ignored) in addition to painful yearning (Shear et al., 2005). These self-report findings suggest the involvement of both reward and pain networks.

The nucleus accumbens (NA) is the region most commonly associated with reward (Knutson et al., 2001). NA has also been shown to play a role in social attachment, such as sibling and maternal affiliation, via neurotransmitters and peptides (e.g., dopamine and oxytocin) (Young et al., 2001). The pain network, by contrast, including the dorsal anterior cingulate cortex (dACC), insula, and periaqueductal gray (PAG) has been previously implicated in both physical (Rainville, 2002) and social pain (Eisenberger et al., 2003, Rainville, 2002). The present analysis specifically investigates whether the CG group had greater activity occur in the brain's reward or pain networks than the NCG group.

Section snippets

Participants

Women (11 CG, 12 NCG) who had experienced the death of a mother or sister to breast cancer in the past 5 years were recruited to participate in an event-related fMRI study. Participants were recruited from a clinic for women at familial risk of breast cancer and from the community. Sixty-four persons were screened by telephone, and 35 had an initial interview. Participants were excluded for current Axis I disorder (including major depression), as evidenced by a structured clinical interview (

Reward activation

Greater reward-related activity occurred in the CG relative to the NCG individuals. Notably, the NA (x = 10, y = 20, z =  6; Fig. 2A) was the only region of the brain that was more active in response to grief-related words than neutral words among those with CG compared to NCG (t = 3.51, p < 0.001, 15 voxels). Parameter estimates were extracted from this region and reported separately for each group as shown in Fig. 2B. CG individuals produced increased NA activity in response to grief words (t = 3.36, p < 

Discussion

Two models of grief have been hypothesized: a detachment model and a reunion model (Bowlby, 1980). In the detachment model, the grief emotion is believed to play a role in the acceptance of the reality of the death and therefore assist in recovery from the loss. In the reunion model, the grief is a form of protest against the separation from the deceased, and serves to promote reunion with the lost person, not detachment. After the death, cues of the deceased (such as memories, photos, etc.)

Acknowledgments

We would like to thank the UCLA Brain Mapping Center for their assistance. This research was supported by funds from the California Breast Cancer Research Program Grant Number 10IB-0048. This work was also supported in part by grant T32-MH19925, the Cousins Center for Psychoneuroimmunology and the Friends of the Semel Institute for Neuroscience and Human Behavior.

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    Citation Excerpt :

    In support of this notion, greater functional activation in the VS, particularly in the nucleus accumbens (NAcc), to reminders of the deceased is reported in PGD, relative to integrated grief (O'Connor et al., 2008). Higher neural activity in this key reward processing region positively correlated with yearning across PGD and integrated grief participants (O'Connor et al., 2008). These findings, however, are not universal, and they appear to diverge based on the age of the PGD sample (McConnell et al., 2018).

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