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| REVIEW ARTICLE |
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| Year : 2020 | Volume
: 9
| Issue : 3 | Page : 183-193 |
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Risk factors for suicide: Systematic review
Alceu Ramos Conceicao Junior1, José Francisco Danilo de Guadalupe Correa Fletes1, Tadeu Lemos2, Eneida Patrícia Teixeira3, Maria de Lourdes de Souza4
1 Department of Informatics and Statistics, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil
2 Department of Pharmacology, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil
3 Department of Public Health, Federal University of Santa Catarina (UFSC), Florianópolis; Undergraduate Nursing Course, University of Vale do Itajaí (UNIVALI), Itajaí, Brazil
4 Department of Public Health, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil
| Date of Submission | 01-Jun-2020 |
| Date of Decision | 22-Jul-2020 |
| Date of Acceptance | 03-Oct-2020 |
| Date of Web Publication | 05-Dec-2020 |
Correspondence Address:
Alceu Ramos Conceicao Junior
Rua Voluntários da Pátria, 84 – Postal Code: 88047-200 – Costeira do Pirajubaé, Florianópolis, Santa Catarina
Brazil
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/sjhs.sjhs_83_20
The occurrence of suicide has increased worldwide, and it is the second leading cause of death among young people between 15 and 29 years old. Therefore, to describe and understand the risk factors for suicide in this population is very important. To examine 30 articles were included in the body of analysis of this review, most of which were produced/published in economically developed countries. Randomized, quasi-randomized, and observational analytical studies (cohort, case-control, and cross-sectional), with populations sample between 10 and 25 years old were included. Risks related to factors of the social environment and life events, psychological factors, and sociodemographic characteristics were identified. The risk factors are presented under different analyses, but the authors claim that suicide is not a single-cause event. Suicide is a very complex phenomenon, determined by the interaction between several factors, such as biological, psychological, and sociocultural and family environment, with a great impact on the world public health.
Keywords: Adolescent, cause of death, mental disorders, risk factors, suicide
How to cite this article:
Junior AR, Fletes JF, Lemos T, Teixeira EP, Souza ML. Risk factors for suicide: Systematic review. Saudi J Health Sci 2020;9:183-93 |
| Introduction | |  |
One of the definitions of suicide refers to the human act of causing the cessation of one's own life. This definition implies, first, that the term suicide can only be used in the case of death or circumstances whose causal sequence leads to death and in which there was intentionality of the subject.[1]
Suicide can be defined, therefore, as the conscious and intentional act of causing one's own death.[2]
Suicide is categorized as an “external cause” in the International Classification of Diseases (X60–X84), which includes the forms of violence and accidents. The World Health Organization classifies this phenomenon in four levels: Low (<5 suicide deaths per 100,000 inhabitants); medium (from 5 to 15); high (from 15 to 30); and very high (above 30).[3]
Over 17 years, 156,292 suicide cases were recorded in Brazil. In this period, the standardized general estimate for age and sex per 100,000 individuals was 4.81, increasing from 3.82 in 2000 to 5.4 in 2016. The standardized rates for the age of men and women were 6.12 and 1.16 in 2000 and 8.65 and 2.24 in 2016, respectively. The proportion was 3.81 times higher in men compared to women in this period. The risk ratio according to sex was lower between 40 and 59-year-old (3.72) than between 20 and 49-year-old and 60-year-old or older (4.24 and 5.44, respectively), due to increased suicide among females in this age group (40- and 59-year-old) and after 60, peaking at 8.2 in the population over 80.[4]
In the state of Santa Catarina, there was an increase of approximately 61.1% (from 0.64 to 1.03) in the rate of suicide deaths in the period between 2006 and 2018. Approximately 49.5% of suicide attempts in this state occurred in the 10–29 years of age group. The means adopted by 73.6% of the suicide cases was hanging.[5]
Suicide stems from an association between biological, genetic, psychological, social, environmental, and situational factors. The fact is that no single factor can offer a complete causal explanation for suicide. Suicide is considered a behavior resulting from the interaction of several factors, such as sociocultural characteristics, traumatic experiences, difficulties in early childhood, psychiatric history, and genetic vulnerability.[6]
Suicide rates increase during periods of economic crisis, when unemployment and poverty rates tend to increase. The socio-economic context of the community can affect the health of all residents, as the characteristics of the physical environment and the availability of services vary according to socioeconomic conditions.[7] Some of the risk factors are found in all age groups, one of which is the area of residence. This risk factor can increase suicidal behavior in early ages, as it increases in older ages.[8] Furthermore, there is a linear association between high scores at intelligence tests and the suicide risk reduce, thus, a the quality of education can interfere in suicide risk.[9]
Due to the increase in suicide rates in the Brazilian reality and in Santa Catarina, the authors decided to carry out the present review on risk factors for suicide. The purpose of the review was to answer the following question: What are the risk factors for suicide in children, adolescents and young adults?
| Methods | | |
This is a systematic review of the risk factors for suicide in children, adolescents and young adults. The review process included the following steps: (i) development of the search strategy, including the definition of descriptors, search terms, databases to be used, and inclusion and exclusion criteria; (ii) implementation of the search strategy, including data collection and steps for reading and analyzing the manuscripts found, according to the inclusion and exclusion criteria; (iii) extraction of data from the publications included in the review; (iv) categorization of data; (v) presentation and interpretation of data.[10],[11]
Data were collected from December 11–13, 2019, in the following databases: PubMed, LILACS, SciELO and MEDLINE.
The search strategy included the following Health Sciences Descriptors (DeCS)/Medical Subject Headings (MeSH) descriptors for PubMed, LILACS, and MEDLINE: “Suicide,” “Suicide, Attempted,” “Suicide, Assisted,” “Self-Injurious Behavior,” “Risk Factors,” “Population at Risk,” “Young Adult,” “Adolescent,” “Adolescent Health,” “Adolescent Behavior,” “Epidemiologic Studies,” “Case-Control Studies,” “Cohort Studies” and “Cross-sectional studies,” in addition to the inclusion of the following search terms: “Risk Factor,” “Young People,” “Case Control,” “Cohort Study,” “Cohort Studies,” “Cohort Analy$,” “Follow up Study,” “Follow up Studies,” “Longitudinal,” “Retrospective” and “Cross Sectional.” As it is not possible to use DeCS/MeSH descriptors to search in SciELO, the descriptors used in the other databases were organized as search terms in SciELO. For both strategies, the Boolean operators “OR” and “AND” were used to build the search structure.
The inclusion criteria were: Randomized, quasi-randomized and observational analytical studies (cohort, case-control, and cross-sectional), manuscripts published in Portuguese, English or Spanish, age range between ten and 25 years, regardless of sex or sexual option, type of exposure of the population, family risk, history of illness, mental suffering or social factors, and studies that identify risk factors for suicide. As exclusion criteria, the following were adopted: Publications of theses, dissertations, editorials, integrative and systematic reviews, descriptive observational studies or qualitative studies, studies not available in full length, and population under the age of ten or over 25 years.
The articles found were exported to the database manager software Endnote, version X9, in order to operationalize the selection of primary studies in the systematic review.
After the first selection step, the files were exported to the Rayyan software. Rayyan is a free web tool designed to assist researchers working on systematic reviews and other knowledge synthesis projects and dramatically accelerates the process of screening and selecting studies.[12] The articles were read in full length, evaluated by two reviewers independently and with blinding or activated screening in the moment of selecting the articles that could be included or excluded from the study. After the second selection stage, screening was deactivated and then the divergent decisions regarding selecting the articles were resolved through a conciliation meeting with the presence of an external expert reviewer, not involved in the selection stage, to resolve conflicts and for making a final decision on inclusion or exclusion of the work in the systematic review, was analyzed whether the study is specifically about risk, whether an age group of the study population is contained in the age group between 10 and 25 years and whether the study is an observational analytical study (cohort, case-control, and cross-sectional).
Descriptive statistics were applied, with calculation of absolute and relative frequencies with aid of the Microsoft Word® (for Office 365 ProPlus) tool, through a table with the following data: Year of publication, name of the authors, title, type of study, study population, and objective.
Each manuscript was classified, according to its objective and result into one of the following categories: Sociodemographic variables, psychological factors, and variables of the social environment and life events.[13]
In addition, a graph, as shown in [Figure 1], was built displaying the distribution of articles per country according to the level of development.[14] | Figure 1: Graph showing the number of articles by countries' economic situation. Florianópolis, Santa Catarina, Brazil, 2019 SOURCE: Elaborated by authors
Click here to view |
| Results | | |
A total of 3090 articles were found in this systematic review by consulting the PubMed (2537), SciELO (20) and LILACS + MEDLINE (533) databases. The synthesis is shown in [Figure 2], showing a PRISMA flowchart about identification, screening and assessment of eligibility for inclusion of studies in this review. | Figure 2: PRISMA flowchart showing the results of the review. Florianópolis, Santa Catarina, Brazil, 2020 SOURCE: Elaborated by authors
Click here to view |
As shown in [Table 1], risk factors for suicide related to the social environment and life events were identified in nine of the 30 studies (numbers 1, 4, 6, 8, 10, 14, 16, 23, 26), while those related to psychological factors and mental disorders stood out in 12 of the studies (3, 9, 15, 17, 18, 20, 21, 25, 27, 28, 29, 30). Eight studies addressed the two categories (2, 5, 11, 12, 13, 19, 22, 24) and seven addressed the three categories of risk factors for suicide. These data are shown in the [Figure 3]. | Figure 3: Graph showing the number of articles by category group. Florianópolis, Santa Catarina, Brazil, 2020 SOURCE: Elaborated by authors
Click here to view |
| Discussion | | |
The results showed that the risk factors cannot be considered isolated, even when authors emphasize a given risk factor over the others.
The period of life that goes from childhood to the beginning of adulthood, in this study considered to be encompassed between the ages of ten and 25 years, constitutes the phase of greater and more intense transformation in the life cycle, characterized by new social and psychological demands. Such demands bring along a greater vulnerability to psychological disorders and more suicide attempts.[45] The authors show that suicide is the second leading cause of death among women and the third among men in this age group.[46]
The vulnerability of young people to suicide has been the subject of studies for several decades, motivated by the growing increase of deaths in this population, detected since the second half of the last century.[47],[48] A study from that period, carried out by Davidson et al.,[15] elucidated the risk factors related to 14 suicides of adolescents that occurred in Texas (USA) between 1983 and 1984, in a case-control study with questionnaires applied to that reality. The study reported a greater relationship between young people who committed suicide with previous suicide attempts, self-harm, emotional instability and the experience of having suffered violence. With regard to previous suicide attempts and self-harm, the conclusion of these authors was later corroborated by other studies carried out with different research designs, in subsequent years, such as those of Hawton et al.,[16] Bella,[31] Finkelstein et al.,[36] and Olfson et al.[42]
At the same time, in their case-control studies with more than 60 adolescents, Brent et al.[17],[19] demonstrated the relationship between psychiatric disorders and suicides, with emphasis for mood disorders (depression and bipolar disorder), conduct disorder, attention deficit, and drug use. After that, cohort studies demonstrated the relevance of these risk factors, intensifying the discussion about the importance of early diagnosis and therapeutic intervention of these disorders to reduce the incidence of suicide in adolescence.[23],[29],[39],[41],[43]
In the study of the families of those adolescents, still in the 1990s, Brent et al.[18] showed that the family history of depression, drug abuse and discord in family relationships were related to the suicides. They showed the adolescents' vulnerability to adversities in the family environment.[18] Gould et al.,[20] Beautrais et al.,[21] Pfeffer et al.,[22] the very group of Brent[26] and Björkenstam et al.[38] deepened this analysis, emphasizing the fragility of parental relationships and sociodemographic factors, such as socioeconomic vulnerability, as related to the occurrence of psychiatric disorders in family members. In the continuation of their studies, the authors claimed that parents with psychiatric disorders contributed to the early occurrence of suicide attempts by their children.[26] Other important factors to be considered as risk factors for suicide are if the family use and have fire gun at home[24] and traumatic separation between family and children.[40]
The interaction of socioenvironmental and psychological/psychiatric factors increases the vulnerability of young people to suicide. This impact was well demonstrated in a cohort study involving 1265 New Zealand children.[25] The authors showed that at 21 years of age, 28% of young people reported suicidal ideation and 7% actually tried to kill themselves, the risk being greater among those raised in an environment of socioeconomic family adversity, marital disruption and fragile parent/child relationships. The factors involving family relationships were significantly influenced by mental health disorders, with the period between adolescence and early adulthood being the most vulnerable. These results are later demonstrated in the studies by Agerbo et al.,[27] Dugas et al.[32] and Strandheim et al.[34]
Among the risk factors for suicide in a society, is important to analyze a residential area, considering in an isolated rural area, the possibilities are different when compared to the urban areas.[33] The rates of suicide are increasing faster in rural than in urban areas. Rural and less urban areas face unique challenges in addressing, such as growing violence, drug abuse and limitations in mental health treatment.[49],[50] Cohort study with 660 participants carried out over 8 years in Vancouver, Canada, highlighted the issue of children living on the streets and the impact of abuse in this context. The authors pointed to emotional, physical and sexual abuse and physical and emotional neglect as important risk factors for suicide in this population.[37]
A recent study with individuals who had some suicidal ideation points out that the factors that most increase the chance of attempting suicide are the use of marijuana (2.6-fold higher risk), use of other illicit drugs (2.4-fold higher risk), exposure to self-mutilation by a family member (2.03-fold higher risk) or friend (1.8-fold higher risk) and an “open mind” personality (1.6-fold higher risk).[43] Substance use is highlighted as an important risk factor for suicide especially in those individuals who already have other vulnerabilities.[35]
Additionally, when studying suicide risk factors, it is important to analyze the education context. Klomek et al. and Gunnell et al. has demonstrated respectively that bullying and incapacity to keep improving studies and to be approved in the school should be considered as rfactors to suicide.[28],[30]
A limitation of the study is the fact that the risk factors identified in the present systematic review had been already studied by different authors, in different places around the world. Moreover, in the material consulted, the number of articles produced and/or published in Brazil was incipient.
| Conclusions | | |
The risk factors are presented under different analyses, but the authors state that suicide is not a single-cause event. The vulnerability of young people to suicide is related to family conditions and the socio-cultural context itself. Conditions related to psychological factors and mental disorders assume greater importance when associated with the use of psychoactive drugs and also violence in the family context. Young people, regardless of sex, are vulnerable to suicide. Most articles that made up the body of analysis in this review mentioned emotional, physical and sexual abuse and physical and emotional neglect, highlighting mood disorders (depression and bipolar disorder), conduct disorders, attention deficit and drug use. Risk factors for youth suicide were the same in all countries where the articles were produced or published, and they cannot be considered isolated anywhere. This stusdy corroborates that youth suicide is the result of the interaction of multiple factors and therefore, strategies to prevent this behavior must consider transdisciplinary and multicenter approaches.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Meneghel SN, Victora CG, Faria NM, Carvalho LA, Falk JW. Epidemiological aspects of suicide in Rio Grande do Sul, Brazil. Rev Saude Publica 2004;38:804-10.  |
| 2. | |
| 3. | Minayo MC, Pinto LW, Assis SG, Cavalcante FG, Mangas RM. Trends in suicide mortality among Brazilian adults and elderly, 1980-2006. Rev Saude Publica 2012;46:300-9. |
| 4. | Martini M, da Fonseca RC, de Sousa MH, de Azambuja Farias C, Cardoso TA, Kunz M, et al. Age and sex trends for suicide in Brazil between 2000 and 2016. Soc Psychiatry Psychiatr Epidemiol 2019;54:857-60. |
| 5. | |
| 6. | Linhares LM, Kawakame PM, Tsuha DH, Souza AS, Barbieri AR. Construction and validation of an instrument for the assessment of care provided to people with suicidal behavior. Rev Saude Publica 2019;53:48. |
| 7. | Machado DB, Rasella D, Dos Santos DN. Impact of income inequality and other social determinants on suicide rate in Brazil. PLoS One 2015;10:e0124934. |
| 8. | Mun Y, Im MY. Suicidal Ideation and Associated Factors of the Elderly According to Residence Area-Focusing on the Comparisons between Urban and Rural Areas. J Korean Public Health Nurs 2013;27:551-63. |
| 9. | Gunnell D, Magnusson PK, Rasmussen F. Low intelligence test scores in 18 year old men and risk of suicide: Cohort study. BMJ 2005;330:167. |
| 10. | Moher D, Liberati A, Tetzlaff J, Altman DG. The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. Br Med J 2009;151:264-9. |
| 11. | Ercole FF, Melo LS, Alcoforado CL. Integrative review versus systematic review. REME 2014;18:9-11. |
| 12. | Ouzzani M, Hammady H, Fedorowicz Z, Elmagarmid A. Rayyan-a web and mobile app for systematic reviews. Syst Rev 2016;5:210. |
| 13. | Phillips MR, Yang G, Zhang Y, Wang L, Ji H, Zhou M. Risk factors for suicide in China: A national case-control psychological autopsy study. Lancet 2002;360:1728-36. |
| 14. | International Monetary Fund. World Economic Outlook: Global Manufacturing Downturn, Rising Trade Barriers. Washington, DC: International Monetary Fund; 2019. |
| 15. | Davidson LE, Rosenberg ML, Mercy JA, Franklin J, Simmons JT. An epidemiologic study of risk factors in two teenage suicide clusters. JAMA 1989;262:2687-92. |
| 16. | Hawton K, Fagg J, Platt S, Hawkins M. Factors associated with suicide after parasuicide in young people. BMJ 1993;306:1641-4. |
| 17. | Brent DA, Perper JA, Moritz G, Allman C, Friend A, Roth C, et al. Psychiatric risk factors for adolescent suicide: A case-control study. J Am Acad Child Adolesc Psychiatry 1993;32:521-9. |
| 18. | Brent DA, Perper JA, Moritz G, Liotus L, Schweers J, Balach L, et al. Familial risk factors for adolescent suicide: A case-control study. Acta Psychiatr Scand 1994;89:52-8. |
| 19. | Brent DA, Perper JA, Moritz G, Baugher M, Schweers J, Roth C. Suicide in affectively ill adolescents: A case-control study. J Affect Disord 1994;31:193-202. |
| 20. | Gould MS, Fisher P, Parides M, Flory M, Shaffer D. Psychosocial risk factors of child and adolescent completed suicide. Arch Gen Psychiatry 1996;53:1155-62. |
| 21. | Beautrais AL, Joyce PR, Mulder RT. Risk factors for serious suicide attempts among youths aged 13 through 24 years. J Am Acad Child Adolesc Psychiatry 1996;35:1174-82. |
| 22. | Pfeffer CR, Normandin L, Kakuma T. Suicidal children grow up: Relations between family psychopathology and adolescents' lifetime suicidal behavior. J Nerv Ment Dis 1998;186:269-75. |
| 23. | Beautrais AL, Joyce PR, Mulder RT. Personality traits and cognitive styles as risk factors for serious suicide attempts among young people. Suicide Life Threat Behav 1999;29:37-47. |
| 24. | Shah S, Hoffman RE, Wake L, Marine WM. Adolescent suicide and household access to firearms in Colorado: Results of a case-control study. J Adolesc Health 2000;26:157-63. |
| 25. | Fergusson DM, Woodward LJ, Horwood LJ. Risk factors and life processes associated with the onset of suicidal behaviour during adolescence and early adulthood. Psychol Med 2000;30:23-39. |
| 26. | Brent DA, Oquendo M, Birmaher B, Greenhill L, Kolko D, Stanley B, et al. Familial pathways to early-onset suicide attempt: risk for suicidal behavior in offspring of mood-disordered suicide attempters. Arch Gen Psychiatry 2002;59:801-7. |
| 27. | Agerbo E, Nordentoft M, Mortensen PB. Familial, psychiatric, and socio-economic risk factors for suicide in young people: Nested case-control study. BMJ 2002;325:74. |
| 28. | Klomek AB, Sourander A, Niemelä S, Kumpulainen K, Piha J, Tamminen T, et al. Childhood bullying behaviors as a risk for suicide attempts and completed suicides: A population-based birth cohort study. J Am Acad Child Adolesc Psychiatry 2009;48:254-61. |
| 29. | Rodríguez EC, Rios IM, Castillo OO, Moreno NP, González PL. Risk factors of suicide attempt in adolescents, Pinar del Río. Rev Ciencias Mßd 2011;15:52-61. |
| 30. | Gunnell D, Löfving S, Gustafsson JE, Allebeck P. School performance and risk of suicide in early adulthood: Follow-up of two national cohorts of Swedish schoolchildren. J Affect Disord 2011;131:104-12. |
| 31. | Bella ME. Risk factors and behaviors among children and adolescents hospitalized for a suicidal attempt. Rev Mßd Chile 2012;140:1417-24. |
| 32. | Dugas E, Low NC, Rodriguez D, Burrows S, Contreras G, Chaiton M, et al. Early predictors of suicidal ideation in young adults. Canadian J Psychiatry 2012;57:429-36. |
| 33. | Soole R, Kõlves K, De Leo D. Factors related to childhood suicides: Analysis of the Queensland Child Death Register. Crisis 2014;35:292-300. |
| 34. | Strandheim A, Bjerkeset O, Gunnell D, Bjørnelv S, Holmen TL, Bentzen N. Risk factors for suicidal thoughts in adolescence-a prospective cohort study: The Young-HUNT study. BMJ Open 2014;4:e005867. |
| 35. | Martiniuk AL, Chen HY, Glozier N, Patton G, Senserrick T, Williamson A, et al. High alcohol use a strong and significant risk factor for repetitive self-harm in female and male youth: A prospective cohort study. Am J Drug Alcohol Abuse 2015;41:465-73. |
| 36. | Finkelstein Y, Macdonald EM, Hollands S, Hutson JR, Sivilotti ML, Mamdani MM, et al. Long-term outcomes following self-poisoning in adolescents: A population-based cohort study. Lancet Psychiatry 2015;2:532-9. |
| 37. | Hadland SE, Wood E, Dong H, Marshall BD, Kerr T, Montaner JS, et al. Suicide attempts and childhood maltreatment among street youth: A prospective cohort study. Pediatrics 2015;136:440-9. |
| 38. | Björkenstam C, Kosidou K, Björkenstam E. Childhood adversity and risk of suicide: Cohort study of 548 721 adolescents and young adults in Sweden. BMJ 2017;357:j1334. |
| 39. | Pan YJ, Juang KJ, Lu SR, Chen SP, Wang YF, Fuh JL, et al. Longitudinal risk factors for suicidal thoughts in depressed and non-depressed young adolescents. Australian & New Zealand J Psychiatry 2017;51:930-7. |
| 40. | Astrup A, Pedersen CB, Mok PLH, Carr MJ, Webb RT. Self-harm risk between adolescence and midlife in people who experienced separation from one or both parents during childhood. J Affect Disord 2017;208:582-9. |
| 41. | Orri M, Galera C, Turecki G, Forte A, Renaud J, Boivin M, et al. Association of childhood irritability and depressive/anxious mood profiles with adolescent suicidal ideation and attempts. JAMA Psychiatry 2018;75:465-73. |
| 42. | Olfson M, Wall M, Wang S, Crystal S, Bridge JA, Liu SM, et al. Suicide after deliberate self-harm in adolescents and young adults. Pediatrics 2018;141:e20173517. |
| 43. | Gomes AP, Soares ALG, Kieling C, Rohde LA, Gonçalves H. Mental disorders and suicide risk in emerging adulthood: The 1993 Pelotas birth cohort. Rev Saude Publica 2019;53:96. |
| 44. | Mars B, Heron J, Klonsky ED, Moran P, O'Connor RC, Tilling K, et al. Predictors of future suicide attempt among adolescents with suicidal thoughts or non-suicidal self-harm: A population-based birth cohort study. Lancet Psychiatry 2019;6:327-37. |
| 45. | Pereira AS, Willhelm AR, Koller SH, Almeida RMM. Risk and protective factors for suicide attempt in emerging adulthood. Cien Saude Colet 2018;23:3767-77. |
| 46. | McKinnon B, Garißpy G, Sentenac M, Elgar FJ. Adolescent suicidal behaviours in 32 low- and middle-income countries. Bull World Health Organ 2016;94:340-350F. |
| 47. | |
| 48. | Nock MK, Borges G, Bromet EJ, Cha CB, Kessler RC, Lee S. Suicide and Suicidal Behavior. Epidemiologic Reviews. Vol. 30. Oxford: Oxford University Press; 2008. p. 133-54. |
| 49. | |
| 50. | Kegler SR, Stone DM, Holland KM. Trends in Suicide by Level of Urbanization – United States, 1999–2015. MMWR Morb Mortal Wkly Rep 2017;66:270-3. |
[Figure 1], [Figure 2], [Figure 3]
[Table 1]
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