Introduction
The elderly face great losses and bereavement [6]. In addition to the death of loved ones, older adults also experience physical dysfunction, dependence, illness, reduced social participation, end of relationships, retirement, and loss of self [10]. The concept of grief usually refers to a set of complex reactions that are experienced after the separation or loss of a loved one [7]. Although several studies have been conducted to describe grief and theories have been developed to understand this concept, there has never been a consensus on a theoretical or empirical definition of grief [7]. It is obvious that the creation of a single definition among professionals depends on the correct explanation of the phenomena [13]. Problems such as the vagueness of concepts are one of the main barriers to the production of definition [14] and this deficiency is also evident in the concept of grief. This study aims to analyze the concept of grief in older adults.

Methods
This is a review study using Walker and Avant's concept analysis method with the following steps: Concept Selection, determining the purpose of the analysis, identification of all possible uses of the concept, creation of the defining attributes, identification of model case of the concept, identification of borderline related, contrary, invented and illegitimate cases, identification of antecedents and consequences, and definition of empirical referents. 
To find studies related to grief in the elderly, a search in online databases including ScienceDirect, Scopus, PsychInfo, Pubmed, Web of Science, and EMBASE using keywords|: Grief, mourn, bereavement, old, geriatric, aging, age, later life, seniors, nonagenarian, octogenarian, and centenarian. Also, articles were examined without considering the time limit published until January 30, 2023. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement was used in this study.
Based on the inclusion criteria, the studies with available fulltexts in English on the definition, results, characteristics and implications of the concept of grief were selected. Studies that have been published in languages ​​other than English, abstracts, conference papers, protocols, and letters to the editor were excluded. In the first stage of the search, 5963 records were obtained. After removing duplicates, 4507 articles remained and 792 articles were obtained after checking the titles and abstracts of the articles. After checking the full text of 236 articles and their screening, 34 articles were included in the study.

Results
Based on the in-depth analysis of the relevant articles, the concept of grief has the following five features: 
 A unique phenomenon: Grief is a complex phenomenon that is different from anything else and creates conditions that others cannot understand and cannot be described in words [24-26]; Negative emotional experience: It is an experience that leads to feelings such as sadness, anger, restlessness, shock, despair, confusion, disbelief, pessimism, and distress [24, 27-39]; Physiological irritation: After a loss experience, the person experiences symptoms such as decreased appetite, decreased sleep, lack of energy, and weight loss [29, 30, 33, 34, 40, 46]; Experience of loneliness: Important loss in old age exposes the person to the feeling of loneliness more than in the young age [27, 29, 30, 32, 36, 40, 41]; Loss of previous meanings: Important losses cause people to lose what is meaningful to them and where and how meaning is experienced in their lives [37, 40].
The antecedents of grief were divided into four categories: Loss of loved ones [24, 25, 27-30, 32, 34, 36-40, 42-52], Spouse divorce [41], Loss of pet [31, 53] and loss of health [55]. The consequences of grief were also divided into four categories: 
Health consequences: It includes physical and psychological domains; Social consequences: Losing a loved one in old age causes the loss of a supporter and caregiver, loss of a special relationship, loss of emotional support, loss of a companion, and social isolation [27, 47, 52, 56]; Financial consequences: For older women, losing a spouse causes them to be unable to pay bills, feel burdened, and worry about living expenses [27, 32, 33, 37]; Resiliency: It includes two main domains of “growth after loss” and “effective life”. The first domain includes the experience of self-growth, personal growth or self-improvement, self-transcendence, self-discovery, a new sense of social independence and personal control [37, 40]. The latter has three sub-categories:
Acquiring new roles and skills: It includes learning new skills, assuming new roles, learning new skills needed to change life, learning alternative methods to solve problems, mastering roles, and new responsibilities [32, 34, 45]; Participation in meaningful social activities: It includes volunteering in schools, charity associations and other social groups, helping others to adapt to the death of their spouse, counseling widows and participating in altruistic activities [32, 39, 48]; New positive meaning: It includes searching for a positive meaning in the loss of a child, believing in God’s wisdom in the loss of a loved one, losing a child as the fulfillment of divine destiny, test of patience by God, and passing the divine test [25, 35, 47].

Conclusion
Greif in older adults is a unique phenomenon that has the main components of experiencing loneliness, experiencing negative emotions, physiological annoyance and loss of previous meanings. This phenomenon is affected by previous experiences of loss of loved ones (death of family members, death of friends), loss of health, loss of pets, and divorce from spouse. It can lead to health, social, and financial consequences and resiliency.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of the University of Social Health and Rehabilitation Sciences, Tehran, Iran. (Code: IR.USWR.REC.1400.258).

Funding
This paper is extracted from the PhD dissertation of Roya Marsa, approved by the Department of Counseling, School of Behavioral Sciences, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.

Authors' contributions
All authors equally contributed to preparing this article.

Conflicts of interest
The interest of conflicts no declared authors.

References

1. Goli M, Maddah SB, Dalvandi A, Hosseini MA, Rahgozar M. [The relationship between successful aging and spiritual health of the elderly (Persian)]. Iranian Journal of Psychiatric Nursing. 2017; 4(5):16-21. [DOI:10.21859/ijpn-04053]
2. Kaldi A, Akbari Kamrani AA, Foroghan M. [Physical, social & mental problems of elderly in District 13 of Tehran (Persian)]. Social Welfare. Social Welfare Quarterly. 2005; 4(14):233-49. [Link]
3. Rahmani F, Marsa R, Khanjani M S, Marsa S, Shahrivar K. [Recognition discriminability and response bias in the Shiraz Verbal Learning Test among older people with amnestic mild cognitive impairment, alzheimer’s disease, and memory normal (Persian)]. Iranian Journal of Ageing. 2023; 18(2):284-303. [DOI:10.32598/sija.2022.2390.3]
4. Marsa R, Bahmani B, Barekati S. [Demoralization syndrome in elderly people living in nursing homes, community-dwelling elderly people and those receiving day care services from rehabilitation centers (Persian)]. Iranian Journal of Ageing. 2020; 14(4):436-49. [DOI:10.32598/sija.13.10.490]
5. Marsa R, Younesi S J, Barekati S, Ramshini M, Ghyasi H. [A comparative study on stress, anxiety and depression between nursing-home elderly residents and home-dwelling elderly people (Persian)]. Iranian Journal of Ageing. 2020; 15(2):176-87. [DOI:10.32598/sija.13.10.500]
6. Bonanno GA, Wortman CB, Nesse RM. Prospective patterns of resilience and maladjustment during widowhood. Psychology and Aging. 2004; 19(2):260-71. [DOI:10.1037/0882-7974.19.2.260] [PMID]
7. Bailley SE, Dunham K, Kral MJ. Factor structure of the grief experience questionnaire (GEQ). Death Studies. 2000; 24(8):721-38. [DOI:10.1080/074811800750036596] [PMID]
8. McCarthy JR. Young people’s experiences of loss and bereavment. New York: McGraw-Hill Education; 2006. [Link]
9. Corr CA. Enhancing the concept of disenfranchised grief. OMEGA-Journal of Death and Dying. 1999; 38(1):1-20 [DOI:10.2190/LD26-42A6-1EAV-3MDN]
10. Scrutton S. Bereavement and grief: Supporting older people through loss. London: Taylor & Francis Ltd; 1995. [Link]
11. Rafii M, Skandari H, Borjali A, Farokhi N. [Investigation on experienced losses in the life story of young people living in Tehran: A phenomenological study (Persian)]. Counseling Culture and Psycotherapy. 2019; 10(37):63-98. [DOI:10.22054/qccpc.2019.28112.1707]
12. Katz S, Florian V. A comprehensive theoretical model of psychological reaction to loss. The International Journal of Psychiatry in Medicine. 1987; 16(4):325-45. [DOI:10.2190/YGRX-AA2B-XUY5-F7DL] [PMID]
13. Avant W. Strategies for theory construction in nursing. London:Pearson; 2014. [Link]
14. Rodgers BL, Cowles KV. The concept of grief: An analysis of classical and contemporary thought. Death Studies. 1991; 15(5):443-58. [DOI:10.1080/07481189108252771]

15. Boldt C, Grill E, Bartholomeyczik S, Brach M, Rauch A, Eriks-Hoogland I, et al. Combined application of the International Classification of Functioning, Disability and Health and the NANDA-International Taxonomy II. Journal of Advanced Nursing. 2010; 66(8):1885-98. [DOI:10.1111/j.1365-2648.2010.05359.x]
16. Powers BA, Knapp TR. Dictionary of nursing theory and research. New York: Springer Publishing Company; 2010. [Link]
17. Singh J. Critical appraisal skills programme. Journal of pharmacology and Pharmacotherapeutics. 2013; 4(1):76-7. [DOI:10.4103/0976-500X.107697]
18. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies. International Journal of Surgery. 2014; 12(12):1495-9. [DOI:10.1016/j.ijsu.2014.07.013] [PMID]
19. Rodgers BL, Knafl KA. Concept development in nursing: Foundations. techniques, and applications. Saunders Philadelphia, PA; 2000. [Link]
20. BJ S. Sadock’s synopsis of psychiatry: Behavioral sciences [F. Rezaee, Persian trans.]. Tehran: Arjmand pub; 2015. [Link]
21. Cowles KV, Rodgers BL. The concept of grief: A foundation for nursing research and practice. Research in Nursing & Health. 1991; 14(2):119-27. [DOI:10.1002/nur.4770140206] [PMID]
22. Corr CA. Bereavement, grief, and mourning in death-related literature for children. Omega-Journal of Death and Dying. 2004; 48(4):337-63. [DOI:10.2190/0RUK-J18N-9400-BHAV]
23. Bocchino GP. Community college grief counseling services: A national survey of grief counseling services for counselors at community colleges in the United States [PhD dissertation]. New York: University of Rochester; 2009. [Link]
24. Malkinson R, Bar-Tur L. Long term bereavement processes of older parents: The three phases of grief. OMEGA-Journal of Death and Dying. 2005; 50(2):103-29. [DOI:10.2190/W346-UP8T-RER6-BBD1]
25. Safa A, Adib-Hajbaghery M, Rezaei M, Araban M. The meaning of losing a child in older adults: A qualitative study. BMC Geriatrics. 2021; 21(1):652. [DOI:10.1186/s12877-021-02609-9] [PMID] [PMCID]
26. Smart LS. Old losses: A retrospective study of miscarriage and infant death 1926-1955. Journal of Women & Aging. 2003; 15(1):71-91. [DOI:10.1300/J074v15n01_06] [PMID]
27. Motsoeneng M, Modise MA. Grieving widows’ lived experiences in a rural South African setting. Journal of Psychology in Africa. 2020; 30(3):264-7. [DOI:10.1080/14330237.2020.1767935]
28. Holm AL, Severinsson E, Berland AK. The meaning of bereavement following spousal loss: A Qualitative study of the experiences of older adults. Sage Open. 2019; 9(4):2158244019894273. [DOI:10.1177/2158244019894273]
29. Stern K, Williams GM, Prados M. Grief reactions in later life. American Journal of Psychiatry. 1951;108(4):289-94. [DOI:10.1176/ajp.108.4.289] [PMID]
30. Costello J, Kendrick K. Grief and older people: The making or breaking of emotional bonds following partner loss in later life. Journal of Advanced Nursing. 2000; 32(6):1374-82. [DOI:10.1046/j.1365-2648.2000.01625.x] [PMID]
31. Wilson DM, Underwood L, Carr E, Gross DP, Kane M, Miciak M, et al. Older women’s experiences of companion animal death: Impacts on well-being and aging-in-place. BMC Geriatrics. 2021; 21(1):470. [DOI:10.1186/s12877-021-02410-8] [PMID] [PMCID]
32. Rodgers LS. Meaning of bereavement among older African American widows. Geriatric Nursing. 2004; 25(1):10-6. [DOI:10.1016/j.gerinurse.2003.11.012] [PMID]
33. Wright PM. Parental bereavement in older age: A scoping review. Illness, Crisis & Loss. 2022; 30(3):531-71. [DOI:10.1177/1054137321995811]
34. Naef R, Ward R, Mahrer-Imhof R, Grande G. Characteristics of the bereavement experience of older persons after spousal loss: An integrative review. International Journal of Nursing Studies. 2013; 50(8):1108-21. [DOI:10.1016/j.ijnurstu.2012.11.026] [PMID]
35. Ang CS. Life will never be the same: Experiences of grief and loss among older adults. Current Psychology. 2023; 42(15):12975-87. [DOI:10.1007/s12144-021-02595-6]
36. Lekalakala-Mokgele E. Death and dying: Elderly persons’ experiences of grief over the loss of family members. South African Family Practice. 2018; 60(5):151-4. [DOI:10.4102/safp.v60i5.4924]
37. Smith ME, Nunley BL, Kerr PL, Galligan H. Elders’ experiences of the death of an adult child. Issues in Mental Health Nursing. 2011; 32(9):568-74. [DOI:10.3109/01612840.2011.576802] [PMID]
38. Damianakis T, Marziali E. Older adults’ response to the loss of a spouse: The function of spirituality in understanding the grieving process. Aging & Mental Health. 2012; 16(1):57-66. [DOI:10.1080/13607863.2011.609531] [PMID]
39. Chan WCH, Chan CL. Acceptance of spousal death: The factor of time in bereaved older adults’ search for meaning. Death Studies. 2011; 35(2):147-62. [DOI:10.1080/07481187.2010.535387] [PMID]
40. Fry P. Spousal loss in late life: A 1-year follow-up of perceived changes in life meaning and psychosocial functioning following bereavement. Journal of Personal & Interpersonal Loss. 1998; 3(4):369-91. [DOI:10.1080/10811449808409711]
41. Pilkington FB. Grieving a loss: The lived experience for elders residing in an institution. Nursing Science Quarterly. 2005; 18(3):233-42. [DOI:10.1177/0894318405277525] [PMID]
42. Norris FH, Murrell SA. Older adult family stress and adaptation before and after bereavement. Journal of Gerontology. 1987; 42(6):606-12. [DOI:10.1093/geronj/42.6.606] [PMID]
43. Grimby A. Aspects of quality of life in old age: Studies on life events, bereavement and health. Scandinavian Journal of Occupational Therapy. 1995; 2(1):40. [DOI:10.3109/11038129509106797]
44. Byrne GJ, Raphael B. The psychological symptoms of conjugal bereavement in elderly men over the first 13 months. International Journal of Geriatric Psychiatry. 1997; 12(2):241-51. [PMID]
45. Shih SN, Turale S, Shih FJ, Tsai JC. Religiosity influences on bereavement adjustments of older widows in Taiwan. Journal of Clinical Nursing. 2010; 19(5‐6):856-66. [DOI:10.1111/j.1365-2702.2009.02947.x] [PMID]
46. Schladitz K, Löbner M, Stein J, Weyerer S, Werle J, Wagner M, et al. Grief and loss in old age: Exploration of the association between grief and depression. Journal of Affective Disorders. 2021; 283:285-92. [DOI:10.1016/j.jad.2021.02.008] [PMID]
47. Manyedi ME, Koen M, Greeff M. Experiences of widowhood and beliefs about the mourning process of the Batswana people. Health SA Gesondheid. 2003; 8(4):69-87. [DOI:10.4102/hsag.v8i4.146]
48. Kim SH. The influence of finding meaning and worldview of accepting death on anger among bereaved older spouses. Aging and Mental Health. 2009; 13(1):38-45.[DOI:10.1080/13607860802154457] [PMID]
49. Ott CH, Lueger RJ, Kelber ST, Prigerson HG. Spousal bereavement in older adults: Common, resilient, and chronic grief with defining characteristics. The Journal of Nervous and Mental Disease. 2007; 195(4):332-41. [DOI:10.1097/01.nmd.0000243890.93992.1e] [PMID]
50. Moore AR. Older poor parents who lost an adult child to AIDS in Togo, West Africa: A qualitative study. Omega. 2008; 56(3):289-304. [DOI:10.2190/OM.56.3.e] [PMID]
51. Tourjeman K, Doron I, Cohen M. Losing a grandchild: The mourning experience of grandparents in Israel. Death Studies. 2015; 39(8):491-9. [DOI:10.1080/07481187.2014.970298] [PMID]
52. Wilson SC, Supiano KP. Experiences of veterans’ widows following conjugal bereavement: A qualitative analysis. Journal of Women & Aging. 2011; 23(1):77-93. [DOI:10.1080/08952841.2011.540479] [PMID]
53. Rémillard LW, Meehan MP, Kelton DF, Coe JB. Exploring the grief experience among callers to a pet loss support hotline. Anthrozoös. 2017; 30(1):149-61. [Link]
54. McKenna H. Nursing theories and models. London: Routledge; 1997. [DOI:10.4324/9780203135440]
55. Dark L, Balandin S, Clemson L. Communicating about loss: Experiences of older Australian adults with cerebral palsy and complex communication needs. Communication Disorders Quarterly. 2011; 32(3):176-89. [DOI:10.1177/1525740109353936]
56. Statz TL, Kobayashi LC, Finlay JM. ‘Losing the illusion of control and predictability of life’: Experiences of grief and loss among ageing US adults during the COVID-19 pandemic. Ageing & Society. 2023; 43(12):2821-44. [DOI:10.1017/S0144686X21001872]
57. Doward LC, Meads DM, Thorsen H. Requirements for quality of life instruments in clinical research. Value in Health.2004; 7 (Suppl 1):S13-6. [DOI:10.1111/j.1524-4733.2004.7s104.x] [PMID]
58. Pan H, Hu R. Grief experience patterns among older adults in Rural China: A latent profile analysis. OMEGA. 2021; 83(4):898-913. [PMID]
59. Bourgeois-Guérin V, Millette V, Lachance J. Communication and silence surrounding the experience of bereavement of older adults living in seniors' residences. Journal of Humanistic Psychology. 2021. [DOI:10.1177/0022167821995352]