[Suicide among young people--familial, psychiatric and socioeconomic risk factors. A nested case-control study]

The objective of the study was to estimate the risk of adolescent and early adulthood suicide related to adverse family and individual backgrounds.

The 496 young people aged 10-21 years who committed suicide during the period 1981-1997 in Denmark and 24,800 gender-age-time-matched controls.

Parental suicide, early death, hospitalised mental illness, unemployment, low income, educational underachievement, parental divorce, mental illness in siblings, as well as mental illness and shorter schooling in the adolescents themselves were associated with increased risk of suicide. In the multivariate analysis, the odds ratios associated with suicide or mental illness in father or mother were 2.30 (95% CI 1.10-4.80), 1.56 (1.12-2.19), 4.75 (2.10-10.8) and 1.73 (1.29-2.32), respectively. The strongest risk factor was mental illness in the adolescents themselves with risk ratios 33.1 (16.5-66.5), 24.3 (6.64-88.7), 84.9 (7.17-1006) and 10.8 (7.75-15.0) for individuals hospitalised with schizophrenia, affective disorders, eating disorders or other psychiatric diagnoses and with an overall attributable risk of 15% (12-17%). The effect of parental socioeconomic variables decreased after adjustment for family history of mental illness.

Important targets in youth suicide prevention could be to decrease the prevalence of or ameliorating the negative effects of psychiatric illness including early recognition and optimal treatment. Reports of high relative risk associated with parental low socioeconomic status may be confounded and overestimated if not adjusted for the association with mental disorder and suicide in the family.