School- and class-level variation in self-harm, suicide ideation and suicide attempts in Danish high schools

Aim: Strong associations have been found between being exposed to self-harm in family and friends and own self-harm in adolescence. Therefore, self-harm and suicide behaviour might tend to cluster within school and school classes. The aim of this study was to describe the prevalence, frequency and type of self-harm, suicide ideation and suicide attempts within Danish high schools and to test whether self-harm and suicide behaviour cluster in schools and school classes. Methods: Data came from the Danish National Youth Study 2014, a national survey. The respective study included 66,284 high-school students nested in 117 schools and 3146 school classes. The prevalence and clustering of self-harm behaviour, ever and within the last year, type of self-harm (e.g. cutting, burning, scratching and hitting) and suicide ideation and suicide attempts were investigated. Multi-level logistic regression was applied to quantify clustering among participants within the same class and school. Results: In total, 12,960 (20%) reported self-harm ever and 5706 (8.6%) within the last year. Prevalence was higher among girls than boys. Among girls, cutting (15%) and scratching (13%) was the most common type of self-harm, whereas among boys, hitting (6.7%) was most prevalent. The degree of clustering of self-harm and suicide behaviour was low, with school-level intra-class correlation coefficients (ICC) ranging from 0.8–1.8% and school class level ICC’s from 4.3–6.8%. Conclusions: This study shows that self-harm was common, especially in girls. The degree of clustering of self-harm and suicide behaviour in school and school classes was low.

[1]  J. Tolstrup,et al.  The Danish National Youth Study 2014: Study design, population characteristics and non-response analysis , 2020, Scandinavian journal of public health.

[2]  Eindra Khin Khin,et al.  Traditional and new media's influence on suicidal behavior and contagion. , 2018, Behavioral sciences & the law.

[3]  M. Nordentoft,et al.  Incidence Rates of Deliberate Self-Harm in Denmark 1994–2011 , 2016, Crisis.

[4]  C. Currie,et al.  Reliability and Validity of an Adapted Version of the Cantril Ladder for Use with Adolescent Samples , 2014 .

[5]  K. Hawton,et al.  The definition and epidemiology of clusters of suicidal behavior: a systematic review. , 2014, Suicide & life-threatening behavior.

[6]  D. Gunnell,et al.  Identifying Probable Suicide Clusters in Wales Using National Mortality Data , 2013, PloS one.

[7]  Keith Hawton,et al.  Suicide clusters: a review of risk factors and mechanisms. , 2013, Suicide & life-threatening behavior.

[8]  Kate E A Saunders,et al.  Self-harm and suicide in adolescents , 2012, The Lancet.

[9]  B. Schneider,et al.  Drinking, Socioemotional Functioning, and Academic Progress in Secondary School , 2012, Journal of health and social behavior.

[10]  B. Møhl,et al.  The prevalence and distribution of self-harm among Danish high school students , 2012 .

[11]  John B Carlin,et al.  The natural history of self-harm from adolescence to young adulthood: a population-based cohort study , 2012, The Lancet.

[12]  A. Ellaway,et al.  Do schools differ in suicide risk? the influence of school and neighbourhood on attempted suicide, suicidal ideation and self-harm among secondary school pupils , 2011, BMC public health.

[13]  Vibeke Jensen,et al.  Danish education registers , 2011, Scandinavian journal of public health.

[14]  K. Rodham,et al.  How adolescents who cut themselves differ from those who take overdoses , 2010, European Child & Adolescent Psychiatry.

[15]  E. Baca-García,et al.  Is impulsivity a link between childhood abuse and suicide? , 2010, Comprehensive psychiatry.

[16]  A. Gray,et al.  Six year follow-up of a clinical sample of self-harm patients. , 2010, Journal of affective disorders.

[17]  K. Hawton,et al.  Predicting deliberate self-harm in adolescents: a six month prospective study. , 2009, Suicide & life-threatening behavior.

[18]  J. Miles,et al.  Self-harm in adolescents: self-report survey in schools in Scotland , 2009, British Journal of Psychiatry.

[19]  I. Nazareth,et al.  A systematic review of mental disorder, suicide, and deliberate self harm in lesbian, gay and bisexual people , 2008, BMC psychiatry.

[20]  S. Fekete,et al.  Deliberate self-harm within an international community sample of young people: comparative findings from the Child & Adolescent Self-harm in Europe (CASE) Study. , 2008, Journal of child psychology and psychiatry, and allied disciplines.

[21]  K. Hawton,et al.  Deliberate self-harm in young people: characteristics and subsequent mortality in a 20-year cohort of patients presenting to hospital. , 2007, The Journal of clinical psychiatry.

[22]  M. Gould,et al.  The Epidemiology and Phenomenology of Non-Suicidal Self-Injurious Behavior Among Adolescents: A Critical Review of the Literature , 2007, Archives of suicide research : official journal of the International Academy for Suicide Research.

[23]  Basile Chaix,et al.  A brief conceptual tutorial of multilevel analysis in social epidemiology: using measures of clustering in multilevel logistic regression to investigate contextual phenomena , 2006, Journal of Epidemiology and Community Health.

[24]  D. Brent,et al.  Adolescent suicide and suicidal behavior. , 2006, Journal of child psychology and psychiatry, and allied disciplines.

[25]  S. Bremberg,et al.  Is there a “school effect” on pupil outcomes? A review of multilevel studies , 2006, Journal of Epidemiology and Community Health.

[26]  Karen Rodham,et al.  Factors associated with suicidal phenomena in adolescents: a systematic review of population-based studies. , 2004, Clinical psychology review.

[27]  P. West,et al.  School effects on pupils' health behaviours: evidence in support of the health promoting school , 2004 .

[28]  D. Leo,et al.  Who are the kids who self-harm ? An Australian self-report school survey , 2004 .

[29]  John C. Wright,et al.  Deliberate Self-Harm at an Adolescent Unit: A Qualitative Investigation , 2004 .

[30]  K. Hawton,et al.  Deliberate self-harm in adolescents: a study of characteristics and trends in Oxford, 1990-2000. , 2003, Journal of child psychology and psychiatry, and allied disciplines.

[31]  T. Joiner Contagion of suicidal symptoms as a function of assortative relating and shared relationship stress in college roommates. , 2003, Journal of adolescence.

[32]  Karen Rodham,et al.  Deliberate self harm in adolescents: self report survey in schools in England , 2002, BMJ : British Medical Journal.

[33]  Ronald Mac Keith,et al.  JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES , 1968 .