Narrative review of the potential for psychedelics to treat Prolonged Grief Disorder

References

• Anderson, B. T., Danforth, A., Daroff, P. R., Stauffer, C., Ekman, E., Agin-Liebes, G., Trope, A., Boden, M. T., Dilley, P. J., Mitchell, J., & Woolley, J. (2020). Psilocybin-assisted group therapy for demoralized older long-term AIDS survivor men: An open-label safety and feasibility pilot study. EClinicalMedicine, 27, 100538. https://doi.org/10.1016/j.eclinm.2020.100538
   PubMedGoogle Scholar
• Balk, D. E. (1999). Bereavement and spiritual change. Death Studies, 23(6), 485–493. https://doi.org/10.1080/074811899200849
   PubMed Web of Science ®Google Scholar
• Bardideh, F., Jarareh, J., Mofrad, M., & Bardideh, K. (2022). The effectiveness of integrated group therapy on prolonged grief disorder of bereaved people from COVID-19 randomized controlled trial. Omega, 302228221141126. https://doi.org/10.1177/00302228221141126
   PubMed Web of Science ®Google Scholar
• Barrett, F. S., Bradstreet, M. P., Leoutsakos, J. M. S., Johnson, M. W., & Griffiths, R. R. (2016). The challenging experience questionnaire: Characterization of challenging experiences with psilocybin mushrooms. Journal of Psychopharmacology (Oxford, England), 30(12), 1279–1295. https://doi.org/10.1177/0269881116678781
   PubMed Web of Science ®Google Scholar
• Barrett, F. S., Johnson, M. W., & Griffiths, R. R. (2015). Validation of the revised Mystical Experience Questionnaire in experimental sessions with psilocybin. Journal of Psychopharmacology (Oxford, England), 29(11), 1182–1190. https://doi.org/10.1177/0269881115609019
   PubMed Web of Science ®Google Scholar
• Biancalani, G., Azzola, C., Sassu, R., Marogna, C., & Testoni, I. (2022). Spirituality for coping with the trauma of a loved one’s death during the COVID-19 pandemic: An Italian qualitative study. Pastoral Psychology, 71(2), 173–185. https://doi.org/10.1007/s11089-021-00989-8
   PubMed Web of Science ®Google Scholar
• Bogenschutz, M. P., Ross, S., Bhatt, S., Baron, T., Forcehimes, A. A., Laska, E., Mennenga, S. E., O’Donnell, K., Owens, L. T., Podrebarac, S., Rotrosen, J., Tonigan, J. S., & Worth, L. (2022). Percentage of heavy drinking days following psilocybin-assisted psychotherapy vs placebo in the treatment of adult patients with alcohol use disorder: A randomized clinical trial. JAMA Psychiatry, 79(10), 953–962. https://doi.org/10.1001/jamapsychiatry.2022.2096
   PubMed Web of Science ®Google Scholar
• Breeksema, J. J., Kuin, B. W., Kamphuis, J., van den Brink, W., Vermetten, E., & Schoevers, R. A. (2022). Adverse events in clinical treatments with serotonergic psychedelics and MDMA: A mixed-methods systematic review. Journal of Psychopharmacology (Oxford, England), 36(10), 1100–1117. https://doi.org/10.1177/02698811221116926
   PubMed Web of Science ®Google Scholar
• Damianakis, T., & Marziali, E. (2012). Older adults’ response to the loss of a spouse: The function of spirituality in understanding the grieving process. 16, 57–66. https://doi.org/10.1080/13607863.2011.609531
   Google Scholar
• Davis, A. K., Barrett, F. S., May, D. G., Cosimano, M. P., Sepeda, N. D., Johnson, M. W., Finan, P. H., & Griffiths, R. R. (2021). Effects of psilocybin-assisted therapy on major depressive disorder: A randomized clinical trial. JAMA Psychiatry, 78(5), 481–489. https://doi.org/10.1001/jamapsychiatry.2020.3285
   PubMed Web of Science ®Google Scholar
• Djelantik, A. A. A. M. J., Robinaugh, D. J., Kleber, R. J., Smid, G. E., & Boelen, P. A. (2020). Symptomatology following loss and trauma: Latent class and network analyses of prolonged grief disorder, posttraumatic stress disorder, and depression in a treatment-seeking trauma-exposed sample. Depression and Anxiety, 37(1), 26–34. https://doi.org/10.1002/da.22880
   PubMed Web of Science ®Google Scholar
• Eisma, M. C. (2023). Prolonged grief disorder in ICD-11 and DSM-5-TR: Challenges and controversies. The Australian and New Zealand Journal of Psychiatry, 57(7), 944–951. https://doi.org/10.1177/00048674231154206
   PubMed Web of Science ®Google Scholar
• Eisma, M. C., Boelen, P. A., & Lenferink, L. I. M. (2020). Prolonged grief disorder following the Coronavirus (COVID-19) pandemic. Psychiatry Research, 288, 113031. https://doi.org/10.1016/j.psychres.2020.113031
   PubMed Web of Science ®Google Scholar
• Family, N., Hendricks, P. S., Williams, L. T., Luke, D., Krediet, E., Maillet, E. L., & Raz, S. (2022). Safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg LSD in healthy participants within a novel intervention paradigm: A proof-of-concept study. Journal of Psychopharmacology (Oxford, England), 36(3), 321–336. https://doi.org/10.1177/02698811211069103
   PubMed Web of Science ®Google Scholar
• Folkman, S. (1997). Positive psychological states and coping with severe stress. Social Science & Medicine (1982), 45(8), 1207–1221. https://doi.org/10.1016/s0277-9536(97)00040-3
   PubMed Web of Science ®Google Scholar
• Gang, J., Kocsis, J., Avery, J., Maciejewski, P. K., & Prigerson, H. G. (2021). Naltrexone treatment for prolonged grief disorder: Study protocol for a randomized, triple-blinded, placebo-controlled trial. Trials, 22(1), 110. https://doi.org/10.1186/s13063-021-05044-8
   PubMedGoogle Scholar
• Golden, A. M. J., & Dalgleish, T. (2010). Is prolonged grief distinct from bereavement-related posttraumatic stress? Psychiatry Research, 178(2), 336–341. https://doi.org/10.1016/j.psychres.2009.08.021
   PubMed Web of Science ®Google Scholar
• González, D., Aixalà, M. B., Neimeyer, R. A., Cantillo, J., Nicolson, D., & Farré, M. (2022). Restorative retelling for processing psychedelic experiences: Rationale and case study of complicated grief. Frontiers in Psychology, 13, 832879. https://doi.org/10.3389/fpsyg.2022.832879
   PubMed Web of Science ®Google Scholar
• González, D., Cantillo, J., Pérez, I., Farré, M., Feilding, A., Obiols, J. E., & Bouso, J. C. (2020). Therapeutic potential of ayahuasca in grief: A prospective, observational study. Psychopharmacology, 237(4), 1171–1182. https://doi.org/10.1007/s00213-019-05446-2
   PubMed Web of Science ®Google Scholar
• González, D., Carvalho, M., Cantillo, J., Aixalá, M., & Farré, M. (2017). Potential use of ayahuasca in grief therapy. 79, 260–285. https://doi.org/10.1177/0030222817710879
   Google Scholar
• Griffiths, R. R., Hurwitz, E. S., Davis, A. K., Johnson, M. W., & Jesse, R. (2019). Survey of subjective ‘God encounter experiences’: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT. PLoS One, 14(4), e0214377. https://doi.org/10.1371/journal.pone.0214377
   PubMed Web of Science ®Google Scholar
• Griffiths, R. R., Johnson, M. W., Carducci, M. A., Umbricht, A., Richards, W. A., Richards, B. D., Cosimano, M. P., & Klinedinst, M. A. (2016). Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. Journal of Psychopharmacology (Oxford, England), 30(12), 1181–1197. https://doi.org/10.1177/0269881116675513
   PubMed Web of Science ®Google Scholar
• Griffiths, R. R., Johnson, M. W., Richards, W. A., Richards, B. D., Jesse, R., MacLean, K. A., Barrett, F. S., Cosimano, M. P., & Klinedinst, M. A. (2018). Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors. Journal of Psychopharmacology (Oxford, England), 32(1), 49–69. https://doi.org/10.1177/0269881117731279
   PubMed Web of Science ®Google Scholar
• Griffiths, R. R., Richards, W. A., Johnson, M. W., McCann, U. D., & Jesse, R. (2008). Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later. Journal of Psychopharmacology (Oxford, England), 22(6), 621–632. https://doi.org/10.1177/0269881108094300
   PubMed Web of Science ®Google Scholar
• Griffiths, R. R., Richards, W. A., McCann, U., & Jesse, R. (2006). Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology, 187(3), 268–283. https://doi.org/10.1007/s00213-006-0457-5
   PubMed Web of Science ®Google Scholar
• Gukasyan, N., Davis, A. K., Barrett, F. S., Cosimano, M. P., Sepeda, N. D., Johnson, M. W., & Griffiths, R. R. (2022). Efficacy and safety of psilocybin-assisted treatment for major depressive disorder: Prospective 12-month follow-up. Journal of Psychopharmacology (Oxford, England), 36(2), 151–158. https://doi.org/10.1177/02698811211073759
   PubMed Web of Science ®Google Scholar
• Hayes, A. M., Yasinski, C., Grasso, D., Ready, C. B., Alpert, E., McCauley, T., Webb, C., & Deblinger, E. (2017). Constructive and unproductive processing of traumatic experiences in trauma-focused cognitive-behavioral therapy for youth. Behavior Therapy, 48(2), 166–181. https://doi.org/10.1016/j.beth.2016.06.004
   PubMed Web of Science ®Google Scholar
• Heeke, C., Stammel, N., Heinrich, M., & Knaevelsrud, C. (2017). Conflict-related trauma and bereavement: Exploring differential symptom profiles of prolonged grief and posttraumatic stress disorder. BMC Psychiatry, 17(1), 118–110. https://doi.org/10.1186/s12888-017-1286-2
   PubMed Web of Science ®Google Scholar
• Johnson, M. W., Garcia-Romeu, A., Johnson, P. S., & Griffiths, R. R. (2017). An online survey of tobacco smoking cessation associated with naturalistic psychedelic use. Journal of Psychopharmacology (Oxford, England), 31(7), 841–850. https://doi.org/10.1177/0269881116684335
   PubMed Web of Science ®Google Scholar
• Johnson, M. W., Hendricks, P. S., Barrett, F. S., & Griffiths, R. R. (2019). Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function. Pharmacology & Therapeutics, 197, 83–102. https://doi.org/10.1016/j.pharmthera.2018.11.010
   PubMed Web of Science ®Google Scholar
• Jordan, A. H., & Litz, B. T. (2014). Prolonged grief disorder: Diagnostic, assessment, and treatment considerations. Professional Psychology: Research and Practice, 45, 180–187. https://doi.org/10.1037/a0036836
   Web of Science ®Google Scholar
• Kakarala, S. E., Roberts, K. E., Rogers, M., Coats, T., Falzarano, F., Gang, J., Chilov, M., Avery, J., Maciejewski, P. K., Lichtenthal, W. G., & Prigerson, H. G. (2020). The neurobiological reward system in Prolonged Grief Disorder (PGD): A systematic review. Psychiatry Res Neuroimaging, 303, 111135. https://doi.org/10.1016/j.pscychresns.2020.111135
   PubMed Web of Science ®Google Scholar
• Kentish-Barnes, N., Chaize, M., Seegers, V., Legriel, S., Cariou, A., Jaber, S., Lefrant, J.-Y., Floccard, B., Renault, A., Vinatier, I., Mathonnet, A., Reuter, D., Guisset, O., Cohen-Solal, Z., Cracco, C., Seguin, A., Durand-Gasselin, J., Éon, B., Thirion, M., … Azoulay, É. (2015). Complicated grief after death of a relative in the intensive care unit. The European Respiratory Journal, 45(5), 1341–1352. https://doi.org/10.1183/09031936.00160014
   PubMed Web of Science ®Google Scholar
• Kersting, A., Brähler, E., Glaesmer, H., & Wagner, B. (2011). Prevalence of complicated grief in a representative population-based sample. Journal of Affective Disorders, 131, 339–343. https://doi.org/10.1016/j.jad.2010.11.032
   PubMed Web of Science ®Google Scholar
• Kristensen, P., Dyregrov, K., & Dyregrov, A. (2017). What distinguishes prolonged grief disorder from depression? Tidsskrift for den Norske laegeforening: tidsskrift for praktisk medicin, ny raekke, 137(7), 538–539. https://doi.org/10.4045/tidsskr.16.0629
   PubMedGoogle Scholar
• Laperle, P., Achille, M., & Ummel, D. (2022). The relational landscape of bereavement after anticipated death: An interpretive model. Death Studies, 46(10), 2485–2497. https://doi.org/10.1080/07481187.2021.1975177
   PubMed Web of Science ®Google Scholar
• Linde, K., Treml, J., Steinig, J., Nagl, M., & Kersting, A. (2017). Grief interventions for people bereaved by suicide: A systematic review. PLoS One, 12(6), e0179496. https://doi.org/10.1371/journal.pone.0179496
   PubMed Web of Science ®Google Scholar
• Low, F., & Earleywine, M. (2023). Psychedelic experiences after bereavement improve symptoms of grief: The influence of emotional breakthroughs and challenging experiences. Journal of Psychoactive Drugs, 1–8. https://doi.org/10.1080/02791072.2023.2228303
   PubMed Web of Science ®Google Scholar
• Lundorff, M., Holmgren, H., Zachariae, R., Farver-Vestergaard, I., & O’Connor, M. (2017). Prevalence of prolonged grief disorder in adult bereavement: A systematic review and meta-analysis. Journal of Affective Disorders, 212, 138–149. https://doi.org/10.1016/j.jad.2017.01.030
   PubMed Web of Science ®Google Scholar
• MacArthur, N. D., Kirby, E., & Mowll, J. (2023). Bereavement affinities: A qualitative study of lived experiences of grief and loss. Death Studies, 47(7), 836–846. https://doi.org/10.1080/07481187.2022.2135044
   PubMed Web of Science ®Google Scholar
• MacLean, K. A., Leoutsakos, J. M. S., Johnson, M. W., & Griffiths, R. R. (2012). Factor analysis of the mystical experience questionnaire: A study of experiences occasioned by the hallucinogen psilocybin. Journal for the Scientific Study of Religion, 51(4), 721–737. https://doi.org/10.1111/j.1468-5906.2012.01685.x
   PubMed Web of Science ®Google Scholar
• Mitchell, J. M., Bogenschutz, M., Lilienstein, A., Harrison, C., Kleiman, S., Parker-Guilbert, K., Ot’alora G, M., Garas, W., Paleos, C., Gorman, I., Nicholas, C., Mithoefer, M., Carlin, S., Poulter, B., Mithoefer, A., Quevedo, S., Wells, G., Klaire, S. S., van der Kolk, B., … Doblin, R. (2021). MDMA-assisted therapy for severe PTSD: A randomized, double-blind, placebo-controlled phase 3 study. Nature Medicine, 27(6), 1025–1033. https://doi.org/10.1038/s41591-021-01336-3
   PubMed Web of Science ®Google Scholar
• Mitchell, J. M., Ot’alora G, M., van der Kolk, B., Shannon, S., Bogenschutz, M., Gelfand, Y., Paleos, C., Nicholas, C. R., Quevedo, S., Balliett, B., Hamilton, S., Mithoefer, M., Kleiman, S., Parker-Guilbert, K., Tzarfaty, K., Harrison, C., de Boer, A., Doblin, R., & Yazar-Klosinski, B. (2023). MDMA-assisted therapy for moderate to severe PTSD: A randomized, placebo-controlled phase 3 trial. Nature Medicine, 29(10), 2473–2480. https://doi.org/10.1038/s41591-023-02565-4
   PubMed Web of Science ®Google Scholar
• Montgomery, C., & Roberts, C. A. (2022). Neurological and cognitive alterations induced by MDMA in humans. Experimental Neurology, 347, 113888. https://doi.org/10.1016/j.expneurol.2021.113888
   PubMed Web of Science ®Google Scholar
• Morgan, C., McAndrew, A., Stevens, T., Nutt, D., & Lawn, W. (2017). Tripping up addiction: The use of psychedelic drugs in the treatment of problematic drug and alcohol use. Current Opinion in Behavioral Sciences, 13, 71–76. https://doi.org/10.1016/j.cobeha.2016.10.009
   Web of Science ®Google Scholar
• Muttoni, S., Ardissino, M., & John, C. (2019). Classical psychedelics for the treatment of depression and anxiety: A systematic review. Journal of Affective Disorders, 258, 11–24. https://doi.org/10.1016/j.jad.2019.07.076
   PubMed Web of Science ®Google Scholar
• Nautiyal, K. M., & Yaden, D. B. (2023). Does the trip matter? Investigating the role of the subjective effects of psychedelics in persisting therapeutic effects. Neuro­psychopharmacology: official Publication of the American College of Neuropsychopharmacology, 48(1), 215–216. https://doi.org/10.1038/s41386-022-01424-z
   PubMed Web of Science ®Google Scholar
• New meanings of death. Retrieved from https://psycnet.apa.org/record/1978-08140-000
   Google Scholar
• Oconnor, M. F. (2012). Immunological and neuroimaging biomarkers of complicated grief. Dialogues in Clinical Neuroscience, 14, 141–148. https://doi.org/10.31887/DCNS.2012.14.2/mfoconnor
   PubMedGoogle Scholar
• Papa, A., Sewell, M. T., Garrison-Diehn, C., & Rummel, C. (2013). A randomized open trial assessing the feasibility of behavioral activation for pathological grief responding. Behavior Therapy, 44(4), 639–650. https://doi.org/10.1016/j.beth.2013.04.009
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., & Maciejewski, P. K. (2022). Prolonged grief disorder. The Lancet. Psychiatry, 9(9), 696. https://doi.org/10.1016/S2215-0366(22)00263-2
   PubMedGoogle Scholar
• Prigerson, H. G., Boelen, P. A., Xu, J., Smith, K. V., & Maciejewski, P. K. (2021). Validation of the new DSM-5-TR criteria for prolonged grief disorder and the PG-13-revised (PG-13-R) scale. World Psychiatry: Official Journal of the World Psychiatric Association (WPA), 20(1), 96–106. https://doi.org/10.1002/wps.20823
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., Maciejewski, P. K., Reynolds, C. F. 3rd, Bierhals, A. J., Newsom, J. T., Fasiczka, A., Frank, E., Doman, J., & Miller, M. (1995). Inventory of complicated grief: A scale to measure maladaptive symptoms of loss. Psychiatry Research, 59, 65–79. https://doi.org/10.1016/0165-1781(95)02757-2
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., Bierhals, A. J., Kasl, S. V., Reynolds, C. F. III, Shear, M. K., Day, N., Beery, L. C., Newsom, J. T., & Jacobs, S. (1997). Traumatic grief as a risk factor for mental and physical morbidity. The American Journal of Psychiatry, 154, 616–623.
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., Frank, E., Kasl, S. V., Reynolds, C. F., Anderson, B., Zubenko, G. S., Houck, P. R., George, C. J., & Kupfer, D. J. (1995). Complicated grief and bereavement-related depression as distinct disorders: Preliminary empirical validation in elderly bereaved spouses. The American Journal of Psychiatry, 152(1), 22–30.
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., Horowitz, M. J., Jacobs, S. C., Parkes, C. M., Aslan, M., Goodkin, K., Raphael, B., Marwit, S. J., Wortman, C., Neimeyer, R. A., Bonanno, G. A., Block, S. D., Kissane, D., Boelen, P., Maercker, A., Litz, B. T., Johnson, J. G., First, M. B., & Maciejewski, P. K. (2009). Prolonged grief disorder: Psychometric validation of criteria proposed for DSM-V and ICD-11. PLoS Medicine, 6(8), e1000121. https://doi.org/10.1371/journal.pmed.1000121
   PubMed Web of Science ®Google Scholar
• Prigerson, H. G., Kakarala, S., Gang, J., & Maciejewski, P. K. (2021). History and status of prolonged grief disorder as a psychiatric diagnosis. Annual Review of Clinical Psychology, 17(1), 109–126. https://doi.org/10.1146/annurev-clinpsy-081219-093600
   PubMedGoogle Scholar
• Prigerson, H. G., Shear, M. K., & Reynolds, C. F. (2022). Prolonged grief disorder diagnostic criteria—Helping those with maladaptive grief responses. JAMA Psychiatry, 79(4), 277–278. https://doi.org/10.1001/jamapsychiatry.2021.4201
   PubMed Web of Science ®Google Scholar
• Ransome, Y. (2020). Religion, spirituality, and health: New considerations for epidemiology. American Journal of Epidemiology, 189(8), 755–758. https://doi.org/10.1093/aje/kwaa022
   PubMed Web of Science ®Google Scholar
• Rappaport, B. I., Kandala, S., Luby, J. L., & Barch, D. M. (2020). Brain reward system dysfunction in adolescence: Current, cumulative, and developmental periods of depression. The American Journal of Psychiatry, 177(8), 754–763. https://doi.org/10.1176/appi.ajp.2019.19030281
   PubMed Web of Science ®Google Scholar
• Reynolds, C. F., Miller, M. D., Pasternak, R. E., Frank, E., Perel, J. M., Cornes, C., Houck, P. R., Mazumdar, S., Dew, M. A., & Kupfer, D. J. (1999). Treatment of bereavement-related major depressive episodes in later life: a controlled study of acute and continuation treatment with nortriptyline and interpersonal psychotherapy. The American Journal of Psychiatry, 156, 202–208. https://doi.org/10.1176/ajp.156.2.202
   PubMed Web of Science ®Google Scholar
• Richardson, V. E. (2006). A dual process model of grief counseling. Journal of Gerontological Social Work, 48, 311–329. https://doi.org/10.1300/J083v48n03_03
   Google Scholar
• Rosner, R., Pfoh, G., & Kotoučová, M. (2011). Treatment of complicated grief, 2, 7995. https://doi.org/10.3402/ejpt.v2i0.7995
   Google Scholar
• Ross, S., Bossis, A., Guss, J., Agin-Liebes, G., Malone, T., Cohen, B., Mennenga, S. E., Belser, A., Kalliontzi, K., Babb, J., Su, Z., Corby, P., & Schmidt, B. L. (2016). Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial. Journal of Psychopharmacology (Oxford, England), 30(12), 1165–1180. https://doi.org/10.1177/0269881116675512
   PubMed Web of Science ®Google Scholar
• Shear, M. K. (2015). Clinical practice. Complicated grief. The New England Journal of Medicine, 372(2), 153–160. https://doi.org/10.1056/NEJMcp1315618
   PubMed Web of Science ®Google Scholar
• Shear, M. K., Reynolds, C. F., Simon, N. M., Zisook, S., Wang, Y., Mauro, C., Duan, N., Lebowitz, B., & Skritskaya, N. (2016). Optimizing treatment of complicated grief: A randomized clinical trial. JAMA Psychiatry, 73(7), 685–694. https://doi.org/10.1001/jamapsychiatry.2016.0892
   PubMed Web of Science ®Google Scholar
• Shear, M. K., Wang, Y., Skritskaya, N., Duan, N., Mauro, C., & Ghesquiere, A. (2014). Treatment of complicated grief in elderly persons: A randomized clinical trial. JAMA Psychiatry, 71(11), 1287–1295. https://doi.org/10.1001/jamapsychiatry.2014.1242
   PubMed Web of Science ®Google Scholar
• Smith, K. W., Sicignano, D. J., Hernandez, A. V., & White, C. M. (2022). MDMA-assisted psychotherapy for treatment of posttraumatic stress disorder: A systematic review with meta-analysis. Journal of Clinical Pharmacology, 62(4), 463–471. https://doi.org/10.1002/jcph.1995
   PubMed Web of Science ®Google Scholar
• Spillers, C. S. (2007). An existential framework for understanding the counseling needs of clients. American Journal of Speech-Language Pathology, 16(3), 191–197. https://doi.org/10.1044/1058-0360(2007/024)
   PubMed Web of Science ®Google Scholar
• Steenkamp, M. M., Litz, B. T., Hoge, C. W., & Marmar, C. R. (2015). Psychotherapy for military-related PTSD: A review of randomized clinical trials. JAMA, 314(5), 489–500. https://doi.org/10.1001/jama.2015.8370
   PubMed Web of Science ®Google Scholar
• Thompson, E. H., Noone, M. E., & Guarino, A. B. (2003). Widows’ spiritual journeys: Do they quest? Journal of Religion, Spirituality & Aging, 14, 119–138.
   Google Scholar
• Volkow, N. D., Michaelides, M., & Baler, R. (2019). The neuroscience of drug reward and addiction. Physiological Reviews, 99(4), 2115–2140. https://doi.org/10.1152/physrev.00014.2018
   PubMed Web of Science ®Google Scholar
• Wagner, B., Knaevelsrud, C., & Maercker, A. (2006). Internet-based cognitive-behavioral therapy for complicated grief: A randomized controlled trial. Death Studies, 30(5), 429–453. https://doi.org/10.1080/07481180600614385
   PubMed Web of Science ®Google Scholar
• Walsh, K., King, M., Jones, L., Tookman, A., & Blizard, R. (2002). Spiritual beliefs may affect outcome of bereavement: Prospective study. BMJ (Clinical Research ed.), 324(7353), 1551–1551. https://doi.org/10.1136/bmj.324.7353.1551
   PubMed Web of Science ®Google Scholar
• Wenn, J. A., O’Connor, M., Kane, R. T., Rees, C. S., & Breen, L. J. (2015). Efficacy of metacognitive therapy for prolonged grief disorder: Protocol for a randomised controlled trial. BMJ Open, 9(1), e007221. https://doi.org/10.1136/bmjopen-2017-021409
   Google Scholar
• Yaden, D. B., & Griffiths, R. R. (2021). The subjective effects of psychedelics are necessary for their enduring therapeutic effects. ACS Pharmacology & Translational Science, 4(2), 568–572. https://doi.org/10.1021/acsptsci.0c00194
   PubMedGoogle Scholar
• Yaden, D. B., & Newberg, A. (2022). The varieties of spiritual experience: 21st century research and perspectives. Oxford University Press. https://doi.org/10.1093/OSO/9780190665678.001.0001
   Google Scholar
• Yaden, D. B. ,Giorgi, S. ,Kern, M. L. ,Adler, A. ,Ungar, L. H. ,Seligman, M. E. P., & Eichstaedt, J. C. (2021). Beyond beliefs: Multidimensional aspects of religion and spirituality in language. Psychology of Religion and Spirituality, 15, 272–280.
   Web of Science ®Google Scholar
• Yaden, D. B., Nayak, S. M., Gukasyan, N., Anderson, B. T., & Griffiths, R. R. (2022). The potential of psychedelics for end of life and palliative care. Current Topics in Behavioral Neurosciences, 56, 169–184. https://doi.org/10.1007/7854_2021_278
   PubMedGoogle Scholar
• Zisook, S., & Shear, K. (2009). Grief and bereavement: what psychiatrists need to know. World Psychiatry: Official Journal of the World Psychiatric Association (WPA), 8(2), 67–74. https://doi.org/10.1002/j.2051-5545.2009.tb00217.x
   PubMed Web of Science ®Google Scholar
• Zygmont, M., Prigerson, H. G., Houck, P. R., Miller, M. D., Shear, M. K., Jacobs, S., & Reynolds, C. F. (1998). A post hoc comparison of paroxetine and nortriptyline for symptoms of traumatic grief. The Journal of Clinical Psychiatry, 59(5), 241–245. https://doi.org/10.4088/jcp.v59n0507
   PubMed Web of Science ®Google Scholar