Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-23T00:13:33.643Z Has data issue: false hasContentIssue false
  • English
  • Français

Are adult stressful life events associated with psychotic relapse? A systematic review of 23 studies

Published online by Cambridge University Press:  15 October 2020

Natasha Martland Open the ORCID record for Natasha Martland [Opens in a new window] ,
Rebecca Martland Open the ORCID record for Rebecca Martland [Opens in a new window] ,
Alexis E. Cullen Open the ORCID record for Alexis E. Cullen [Opens in a new window]  and
Sagnik Bhattacharyya Open the ORCID record for Sagnik Bhattacharyya [Opens in a new window]
Natasha Martland
Affiliation:
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK
Rebecca Martland
Affiliation:
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK
Alexis E. Cullen
Affiliation:
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK
Sagnik Bhattacharyya*
Affiliation:
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK South London and Maudsley NHS Foundation Trust, Denmark Hill, London, SE5 8AZ, UK
*
Author for correspondence: Sagnik Bhattacharyya, E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Relapse rates among individuals with psychotic disorders are high. In addition to the financial burden placed on clinical services, relapse is associated with worse long-term prognosis and poorer quality of life. Robust evidence indicates that stressful life events commonly precede the onset of the first psychotic episode; however, the extent to which they are associated with relapse remains unclear. The aim of this systematic review is to summarize available research investigating the association between recent stressful life events and psychotic relapse or relapse of bipolar disorder if the diagnosis included psychotic symptoms. PsycINFO, Medline and EMBASE were searched for cross-sectional, retrospective and prospective studies published between 01/01/1970 and 08/01/2020 that investigated the association between adult stressful life events and relapse of psychosis. Study quality was assessed using the Effective Public Health Practice Project guidelines. Twenty-three studies met eligibility criteria (prospective studies: 14; retrospective studies: 6; cross-sectional: 3) providing data on 2046 participants in total (sample size range: 14–240 participants). Relapse was defined as a return of psychotic symptoms (n = 20), a return of symptoms requiring hospitalization (n = 2) and a return of symptoms or hospitalization (n = 1). Adult stressful life events were defined as life events occurring after the onset of psychosis. Stressful life events included but were not limited to adult trauma, bereavement, financial problems and conflict. Eighteen studies found a significant positive association between adult stressful life events and psychotic relapse and five studies found a non-significant association. We conclude that adult stressful life events, occurring after psychosis onset, appear to be associated with psychotic relapse.

Keywords

Adultbipolar disorderlife eventpsychosisrelapsereview
Type
Review Article
Information
Psychological Medicine , Volume 50 , Issue 14 , October 2020 , pp. 2302 - 2316
Check for updates
Copyright
Copyright © The Author(s), 2020. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Al Khani, M. A. F., Bebbington, P. E., Watson, J. P., & House, F. (1986). Life events and schizophrenia. British Journal of Psychiatry, 148(1), 12–22. https://doi.org/10.1192/bjp.148.1.12 .CrossRefGoogle Scholar
Almond, S., Knapp, M., Francois, C., Toumi, M., & Brugha, T. (2004). Relapse in schizophrenia: Costs, clinical outcomes and quality of life. British Journal of Psychiatry, 184(4), 346–351. https://doi.org/10.1192/bjp.184.4.346 .CrossRefGoogle ScholarPubMed
Alvarez-Jimenez, M., Priede, A., Hetrick, S. E., Bendall, S., Killackey, E., Parker, A. G., … Gleeson, J. F. (2012). Risk factors for relapse following treatment for first episode psychosis: A systematic review and meta-analysis of longitudinal studies. Schizophrenia Research, 139(1–3), 116–128. https://doi.org/10.1016/j.schres.2012.05.007 .CrossRefGoogle ScholarPubMed
Andreasen, N. C. (1989). Scale for the Assessment of Negative Symptoms (SANS). British Journal of Psychiatry, 155(S7), 53–58. https://doi.org/10.1192/s0007125000291502.CrossRefGoogle Scholar
Aronson, T. A., & Shukla, S. (1987). Life events and relapse in bipolar disorder: The impact of a catastrophic event. Acta Psychiatrica Scandinavica, 75(6), 571–576. https://doi.org/10.1111/j.1600-0447.1987.tb02837.x .CrossRefGoogle ScholarPubMed
Ascher-Svanum, H., Zhu, B., Faries, D. E., Salkever, D., Slade, E. P., Peng, X., & Conley, R. R. (2010). The cost of relapse and the predictors of relapse in the treatment of schizophrenia. BMC Psychiatry, 10(1), 2. https://doi.org/10.1186/1471-244X-10-2 .CrossRefGoogle ScholarPubMed
Beards, S., Gayer-Anderson, C., Borges, S., Dewey, M. E., Fisher, H. L., & Morgan, C. (2013). Life events and psychosis: A review and meta-analysis. Schizophrenia Bulletin, 39(4), 740–747. https://doi.org/10.1093/schbul/sbt065.CrossRefGoogle ScholarPubMed
Bech, P., Bolwig, T. G., Kramp, P., & Rafaelsen, O. J. (1979). The Bech-Rafaelsen mania scale and the Hamilton depression scale. Acta Psychiatrica Scandinavica, 59(4), 420–430. https://doi.org/10.1111/j.1600-0447.1979.tb04484.x .CrossRefGoogle ScholarPubMed
Berger, M., Kraeuter, A. K., Romanik, D., Malouf, P., Amminger, G. P., & Sarnyai, Z. (2016). Cortisol awakening response in patients with psychosis: Systematic review and meta-analysis. Neuroscience and Biobehavioral Reviews, 68, 157–166. https://doi.org/10.1016/j.neubiorev.2016.05.027.CrossRefGoogle ScholarPubMed
Birley, J. L. T., & Brown, G. W. (1970). Crises and life changes preceding the onset or relapse of acute schizophrenia: Clinical aspects. British Journal of Psychiatry, 116(532), 327–333. https://doi.org/10.1192/bjp.116.532.327 .CrossRefGoogle ScholarPubMed
Bobes, J., Garcia-Portilla, M. P., Bascaran, M. T., Saiz, P. A., & Bousoño, M. (2007). Quality of life in schizophrenic patients. Dialogues in Clinical Neuroscience, 9(2), 215–226. https://doi.org/10.5294/aqui.2011.11.1.5.Google ScholarPubMed
Borges, S., Gayer-Anderson, C., & Mondelli, V. (2013). A systematic review of the activity of the hypothalamic-pituitary-adrenal axis in first episode psychosis. Psychoneuroendocrinology, 38(5), 603–611. https://doi.org/10.1016/j.psyneuen.2012.12.025.CrossRefGoogle ScholarPubMed
Brady, N., & McCain, G. C. (2005). Living with schizophrenia: A family perspective. Online Journal of Issues in Nursing, 10(1), 7. PMID: 15727542.Google Scholar
Brown, G. W. (1989). Life events and measurement. In Brown, G., & Harris, T. (Eds.), Life events and illness (pp. 49–93). London, NY: The Guilford Press.Google ScholarPubMed
Carney, M. W. P., Roth, M., & Garside, R. F. (1965). The diagnosis of depressive syndromes and the prediction of E.C.T. response. British Journal of Psychiatry, 111(477), 659–674. https://doi.org/10.1192/bjp.111.477.659 .CrossRefGoogle Scholar
Castine, M., Meadorwoodruff, J., & Dalack, G. (1998). The role of life events in onset and recurrent episodes of schizophrenia and schizoaffective disorder. Journal of Psychiatric Research, 32(5), 283–288. https://doi.org/10.1016/S0022-3956(98)00017-X .CrossRefGoogle ScholarPubMed
Chabungbam, G., Avasthi, A., & Sharan, P. (2007). Sociodemographic and clinical factors associated with relapse in schizophrenia. Psychiatry and Clinical Neurosciences, 61(6), 587–593. https://doi.org/10.1111/j.1440-1819.2007.01722.x .CrossRefGoogle Scholar
Chaumette, B., Kebir, O., Mam-Lam-Fook, C., Morvan, Y., Bourgin, J., Godsil, B. P., … Krebs, M. O. (2016). Salivary cortisol in early psychosis: New findings and meta-analysis. Psychoneuroendocrinology, 63, 262–270. https://doi.org/10.1016/j.psyneuen.2015.10.0070.CrossRefGoogle ScholarPubMed
Christensen, E. M., Gjerris, A., Larsen, J. K., Bendtsen, B. B., Larsen, B. H., Rolff, H., … Schaumburg, E. (2003). Life events and onset of a new phase in bipolar affective disorder. Bipolar Disorders, 5(5), 356–361. https://doi.org/10.1034/j.1399-5618.2003.00049.x .CrossRefGoogle ScholarPubMed
Cullen, A. E., Rai, S., Vaghani, M. S., Mondelli, V., & McGuire, P. (2020). Cortisol Responses to Naturally Occurring Psychosocial Stressors Across the Psychosis Spectrum: A Systematic Review and Meta-Analysis. Frontiers in psychiatry, 11, 513. https://doi.org/10.3389/fpsyt.2020.00513.CrossRefGoogle ScholarPubMed
Cullen, A. E., Zunszain, P. A., Dickson, H., Roberts, R. E., Fisher, H. L., Pariante, C. M., … Laurens, K. R. (2014). Cortisol awakening response and diurnal cortisol among children at elevated risk for schizophrenia: Relationship to psychosocial stress and cognition. Psychoneuroendocrinology, 46(100), 1–3. https://doi.org/10.1016/j.psyneuen.2014.03.010.CrossRefGoogle ScholarPubMed
Das, M. K., Kulhara, P. L., & Verma, S. K. (1997). Life events preceding relapse of schizophrenia. International Journal of Social Psychiatry, 43(1), 56–63. https://doi.org/10.1177/002076409704300105 .CrossRefGoogle ScholarPubMed
Day, F. L., Valmaggia, L. R., Mondelli, V., Papadopoulos, A., Papadopoulos, I., Pariante, C. M., … McGuire, P. (2014). Blunted cortisol awakening response in people at ultra high risk of developing psychosis. Schizophrenia Research, 158(1-3), 25–31. https://doi.org/10.1016/j.schres.2014.06.041.CrossRefGoogle ScholarPubMed
Dohrenwend, B. S., Krasnoff, L., Askenasy, A. R., & Dohrenwend, B. P. (1978). Exemplification of a method for scaling life events: The Peri Life Events Scale. Journal of Health and Social Behavior, 19(2), 205–229. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/681735.CrossRefGoogle ScholarPubMed
Dols, A., Korten, N., Comijs, H., Schouws, S., van Dijk, M., Klumpers, U., … Stek, M. (2018). The clinical course of late-life bipolar disorder, looking back and forward. Bipolar Disorders, 20(5), 459–469. https://doi.org/10.1111/bdi.12586 .CrossRefGoogle Scholar
Draman, S., Ismail, S. B., Merchant, M. R., Yusof, H. M., Husin, T. A. RS.., & Singh, A. L J. S.. (2005). A study on risk factors of repeated admissions among patients with schizophrenia in Hospital Kota Bharu, Kelantan, Malaysia. International Medical Journal, 12(3), 185–192.Google Scholar
Effective Public Health Practice Project. (2003). Quality assessment tool for quantitative studies. Effective Public Health Practice Project, 2–5. Retrieved from https://www.ephpp.ca/PDF/Quality Assessment Tool_2010_2.pdf.Google Scholar
Eisner, E., Bucci, S., Berry, N., Emsley, R., Barrowclough, C., & Drake, R. J. (2019). Feasibility of using a smartphone app to assess early signs, basic symptoms and psychotic symptoms over six months: A preliminary report. Schizophrenia Research, 208, 105–113. https://doi.org/10.1016/j.schres.2019.04.003.CrossRefGoogle ScholarPubMed
Ellicott, A., Hammen, C., Gitlin, M., Brown, G., & Jamison, K. (1990). Life events and the course of bipolar disorder. American Journal of Psychiatry, 147(9), 1194–1198. https://doi.org/10.1176/ajp.147.9.1194 .Google ScholarPubMed
Endicott, J, & Spitzer, R. L. (1978). A Diagnostic Interview: The Schedule for Affective Disorders and Schizophrenia. Archives of General Psychiatry, 35(7), 837–844. https://doi.org/10.1001/archpsyc.1978.01770310043002.CrossRefGoogle Scholar
Girshkin, L., Matheson, S. L., Shepherd, A. M., & Green, M. J. (2014). Morning cortisol levels in schizophrenia and bipolar disorder: A meta-analysis. Psychoneuroendocrinology, 49(1), 187–206. https://doi.org/10.1016/j.psyneuen.2014.07.013.CrossRefGoogle ScholarPubMed
Hamilton, M. (1980). Rating depressive patients. The Journal of Clinical Psychiatry, 41(12 Pt 2), 21–24. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/7440521.Google ScholarPubMed
Higgins, J. P., & Green, S.. (2008). Cochrane handbook for systematic reviews of interventions: Cochrane book series. In Cochrane handbook for systematic reviews of interventions: Cochrane book series (pp. 1–649). UK: John Wiley and Sons.CrossRefGoogle Scholar
Hirsch, S., Bowen, J. O., Emami, J., Cramer, P., Jolley, A., Haw, C., … Dickinson, M. (1996). A one year prospective study of the effect of life events and medication in the aetiology of schizophrenic relapse. British Journal of Psychiatry, 168(1), 49–56. https://doi.org/10.1192/bjp.168.1.49.CrossRefGoogle ScholarPubMed
Holmes, T. H., & Rahe, R. H. (1967). The social readjustment rating scale. Journal of Psychosomatic Research, 11(2), 213–218. https://doi.org/10.1016/0022-3999(67)90010-4.CrossRefGoogle ScholarPubMed
Howard, R. W. (2011). Testing the accuracy of the retrospective recall method used in expertise research. Behavior Research Methods, 43(4), 931–941. https://doi.org/10.3758/s13428-011-0120-x .CrossRefGoogle ScholarPubMed
Howes, O. D., & Murray, R. M. (2014). Schizophrenia: An integrated sociodevelopmental-cognitive model. The Lancet, 383(9929), 1677–1687. https://doi.org/10.1016/S0140-6736(13)62036-X.CrossRefGoogle ScholarPubMed
Hui, C. L. M., Li, Y. K., Li, A. W. Y., Lee, E. H. M., Chang, W. C., Chan, S. K. W., … Chen, E. Y. H. (2016). Visual working memory deterioration preceding relapse in psychosis. Psychological Medicine, 46(11), 2435–2444. https://doi.org/10.1017/S0033291716000751.CrossRefGoogle ScholarPubMed
Hultman, C. M., Wieselgren, I., & Öhman, A. (1997). Relationships between social support, social coping and life events in the relapse of schizophrenic patients. Scandinavian Journal of Psychology, 38(1), 3–13. https://doi.org/10.1111/1467-9450.00002 .CrossRefGoogle ScholarPubMed
Hunt, N., Bruce-Jones, W., & Silverstone, T. (1992). Life events and relapse in bipolar affective disorder. Journal of Affective Disorders, 25(1), 13–20. https://doi.org/10.1016/0165-0327(92)90088-N .CrossRefGoogle ScholarPubMed
Kendell, R. E. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). American Journal of Psychiatr, 137(12), 1630–1631. https://doi.org/10.1176/ajp.137.12.1630.CrossRefGoogle Scholar
Kutchins, H., & Kirk, S. A. (1995). Diagnostic and statistical manual of mental disorders (4th ed. Vol. 40, pp. 286–287). US: Social Work. https://doi.org/10.1093/sw/40.2.286.Google Scholar
Leff, J., Kuipers, L., Berkowitz, R., Vaughn, C., & Sturgeon, D. (1983). Life events, relatives’ expressed emotion and maintenance neuroleptics in schizophrenic relapse. Psychological Medicine, 13(4), 799–806. https://doi.org/10.1017/S0033291700051503.CrossRefGoogle ScholarPubMed
Malla, A. K., Cortese, L., Shaw, T. S., & Ginsberg, B. (1990). Life events and relapse in schizophrenia. A one year prospective study. Social Psychiatry and Psychiatric Epidemiology, 25(4), 221–224. https://doi.org/10.1007/bf00782965 .CrossRefGoogle ScholarPubMed
Mallett, R., Hagen-Zanker, J., Slater, R., & Duvendack, M. (2012). The benefits and challenges of using systematic reviews in international development research. Journal of Development Effectiveness, 4(3), 445–455. https://doi.org/10.1080/19439342.2012.711342 .CrossRefGoogle Scholar
Mattsson, M., Topor, A., Cullberg, J., & Forsell, Y. (2008). Association between financial strain, social network and five-year recovery from first episode psychosis. Social Psychiatry and Psychiatric Epidemiology, 43(12), 947–952. https://doi.org/10.1007/s00127-008-0392-3.CrossRefGoogle ScholarPubMed
McPherson, H., Herbison, P., & Romans, S. (1993). Life events and relapse in established bipolar affective disorder. British Journal of Psychiatry, 163(3), 381–385. https://doi.org/10.1192/bjp.163.3.381 .CrossRefGoogle ScholarPubMed
Nordholm, D., Krogh, J., Mondelli, V., Dazzan, P., Pariante, C., & Nordentoft, M. (2013). Pituitary gland volume in patients with schizophrenia, subjects at ultra high-risk of developing psychosis and healthy controls: A systematic review and meta-analysis. Psychoneuroendocrinology, 38(11), 2394–2404. https://doi.org/10.1016/j.psyneuen.2013.06.030.CrossRefGoogle ScholarPubMed
Nuechterlein, K. H., Dawson, M. E., Gitlin, M., Ventura, J., Goldstein, M. J., Snyder, K. S., … Mintz, J. (1992). Developmental processes in schizophrenic disorders: Longitudinal studies of vulnerability and stress. Schizophrenia Bulletin, 18(3), 387–425. https://doi.org/10.1093/schbul/18.3.387.CrossRefGoogle ScholarPubMed
Overall, J. E., & Gorham, D. R. (1962). The brief psychiatric rating scale. Psychological Reports, 10(3), 799–812. https://doi.org/10.2466/pr0.1962.10.3.799 .CrossRefGoogle Scholar
Pallanti, S., Quercioli, L., & Pazzagli, A. (1997). Relapse in young paranoid schizophrenic patients: A prospective study of stressful life events, P300 measures, and coping. American Journal of Psychiatry, 154(6), 792–798. https://doi.org/10.1176/ajp.154.6.792.Google ScholarPubMed
Paykel, E. S. (1997). The interview for recent life events. Psychological Medicine, 27(2), 301–310. https://doi.org/10.1017/S0033291796004424 .CrossRefGoogle ScholarPubMed
Petros, N., Foglia, E., Klamerus, E., Beards, S., Murray, R. M., & Bhattacharyya, S. (2016). Impact of childhood trauma on risk of relapse requiring psychiatric hospital admission for psychosis. British Journal of Psychiatry, 209(2), 169–170. https://doi.org/10.1192/bjp.bp.115.176636 .CrossRefGoogle Scholar
Pruessner, M., Cullen, A. E., Aas, M., & Walker, E. F. (2017). The neural diathesis-stress model of schizophrenia revisited: An update on recent findings considering illness stage and neurobiological and methodological complexities. Neuroscience and Biobehavioral Reviews, 73, 191–218. https://doi.org/10.1016/j.neubiorev.2016.12.013.CrossRefGoogle ScholarPubMed
Roy-Byrne, P., Post, R. M., Uhde, T. W., Porcu, T., & Davis, D. (1985). The longitudinal course of recurrent affective illness: Life chart data from research patients at the NIMH. Acta Psychiatrica Scandinavica, 71(s317), 1–33. https://doi.org/10.1111/j.1600-0447.1985.tb10510.x .CrossRefGoogle Scholar
Sam, S., Nisha, A., & Varghese, Pj. (2019). Stressful life events and relapse in bipolar affective disorder: A cross-sectional study from a tertiary care center of Southern India. Indian Journal of Psychological Medicine, 41(1), 61–67. https://doi.org/10.4103/IJPSYM.IJPSYM_113_18.CrossRefGoogle ScholarPubMed
Saunders, T. S., Mondelli, V., & Cullen, A. E. (2019). Pituitary volume in individuals at elevated risk for psychosis: A systematic review and meta-analysis. Schizophrenia Research, 213, 23–31. https://doi.org/10.1016/j.schres.2018.12.026.CrossRefGoogle ScholarPubMed
Sheehan, D. V, Lecrubier, Y., Sheehan, K. H., Amorim, P., Janavs, J., Weiller, E., … Dunbar, G. C. (1998). The Mini-International Neuropsychiatric Interview (M.I.N.I.): The development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. The Journal of Clinical Psychiatry, 59 Suppl 2, 22–33;quiz 34-57. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/9881538.Google ScholarPubMed
Simhandl, C., Radua, J., König, B., & Amann, B. L. (2015). The prevalence and effect of life events in 222 bipolar I and II patients: A prospective, naturalistic 4 year follow-up study. Journal of Affective Disorders, 170, 166–171. https://doi.org/10.1016/j.jad.2014.08.043 .CrossRefGoogle ScholarPubMed
Singh, G., Kaur, D., & Kaur, H. (1984). Presumptive stressful life events scale (PSLES) – a new stressful life events scale for use in India. Indian Journal of Psychiatry, 26(2), 107–114. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21965968.Google ScholarPubMed
Stroup, D. F. (2000). Meta-analysis of observational studies in EpidemiologyA proposal for reporting. JAMA, 283(15), 2008. https://doi.org/10.1001/jama.283.15.2008 .CrossRefGoogle Scholar
Subramanian, K., Sarkar, S., Kattimani, S., Philip Rajkumar, R., & Penchilaiya, V. (2017). Role of stressful life events and kindling in bipolar disorder: Converging evidence from a mania-predominant illness course. Psychiatry Research, 258, 434–437. https://doi.org/10.1016/j.psychres.2017.08.073 .CrossRefGoogle ScholarPubMed
Varese, F., Smeets, F., Drukker, M., Lieverse, R., Lataster, T., Viechtbauer, W., … Bentall, R. P. (2012). Childhood adversities increase the risk of psychosis: A meta-analysis of patient-control, prospective-and cross-sectional cohort studies. Schizophrenia Bulletin, 38(4), 661–671. https://doi.org/10.1093/schbul/sbs050.CrossRefGoogle Scholar
Ventura, J., Nuechterlein, K. H., Lukoff, D., & Hardesty, J. P. (1989). A prospective study of stressful life events and schizophrenic relapse. Journal of Abnormal Psychology, 98(4), 407–411. https://doi.org/10.1037/0021-843X.98.4.407 .CrossRefGoogle ScholarPubMed
Walker, E. F., & Diforio, D. (1997). Schizophrenia: A neural diathesis-stress model. Psychological Review, 104(4), 667–685. https://doi.org/10.1037/0033-295X.104.4.667.CrossRefGoogle ScholarPubMed
WHO. (1973). The international pilot study of schizophrenia (1st ed.). WHO: Geneva.Google Scholar
WHO. (2011). The reference should be: International Statistical Classification of Diseases and Related Health Probl ems- 10th revision. In Encyclopedia of Clinical Neuropsychology (pp. 1347). New York: Springer. https://doi.org/10.1007/978-0-387-79948-3_3055.Google Scholar
Wiersma, D., Nienhuis, F. J., Slooff, C. J., & Giel, R. (1998). Natural course of schizophrenic disorders: A 15-year followup of a Dutch incidence cohort. Schizophrenia Bulletin, 24(1), 75–85. https://doi.org/10.1093/oxfordjournals.schbul.a033315.CrossRefGoogle ScholarPubMed
Wing, J. K., Cooper, J. E., & Sartorius, N. (1974). The measurement and classification of psychiatric symptoms. London: Cambridge Univ. Press. https://doi.org/10.1177/003591577506800751 .Google Scholar