Inclusion of the other in the self as a potential risk factor for prolonged grief disorder: A comparison of patients with matched bereaved healthy controls

Pathological grief has received increasing attention in recent years, as about 10% of the bereaved suffer from one kind of it. Pathological grief in the form of prolonged grief disorder (PGD) is a relatively new diagnostic category which will be included into the upcoming ICD-11. To date, various risk and protective factors, as well as treatment options for pathological grief, have been proposed. Nevertheless, empirical evidence in that area is still scarce. Our aim was to identify the association of interpersonal closeness with the deceased and bereavement outcome. Interpersonal closeness with the deceased in 54 participants (27 patients suffering from PGD and 27 bereaved healthy controls) was assessed as the overlap of pictured identities via the inclusion of the other in the self scale (IOS scale). In addition to that, data on PGD symptomatology, general mental distress and depression were collected. Patients suffering from PGD reported higher inclusion of the deceased in the self. By contrast, they reported feeling less close towards another living close person. Results of the IOS scale were associated with PGD severity, general mental distress and depression. Inclusion of the deceased in the self is a significant statistical predictor for PGD caseness.

Pair-Bonding as Inclusion of Other in the Self: A Literature Review

This article surveys scholarship on the self-expansion model principle of inclusion of other in the self (IOS) as it relates to long-term pair-bonding (i.e., enduring adult romantic monogamous relationships). First, we introduce the concept of IOS and then provide a brief overview of prior research. We then review compelling extensions and findings related to relational concepts such as perspective taking (Bernstein et al., 2015), social comparison (Thai and Lockwood, 2015), self-determination (Weinstein et al., 2016), humor (Treger et al., 2013), and pain contagion (Martire et al., 2013). Next, we explore two recent theoretical directions of the principle—the two-dimensional model of relational self-change (McIntyre et al., 2015) and the perceived inclusion of the other in the self (IOS-perceived) construct (Tomlinson and Aron, 2013). Considering these findings and their relation to pair-bonding, we propose important future directions of the IOS principle of the self-expansion model.