Risk factors and study designs used in research of youths' suicide behaviour - An
epidemiological discussion with focus on level of evidence
Sammanfattning
Introduction: Many different epidemiology study designs have been used to analyse risk factors
for suicide behaviour. The purpose of this study was to obtain an insight into the current study
design used in research on youths ’ risk factors for suicide behaviour and to rank the studies
according to level of evidence (LoE). Methods: We searched PubMed and psycINFO in order
to identify relevant individual studies. Results: We included 36 studies of children and youth on
suicidal behaviour and ideation- many rank low on LoE. For suicide, cohort design was often
used, and mental illness (depression, substance abuse and severity of mental illness) was the
most common risk factor. Cohort studies are ranked 2b, which is high according to LoE. For
suicide attempts, survey was often used, and psychopathology, substance abuse and being
exposed to suicidal behaviour were the most common risk factors. For suicidal ideation, survey
was the only design used, and substance abuse and psychopathology the most common risk
factors. Surveys are ranked 4, which are low according to LoE. Many risk factors were broad
and unspecifi c, and standard defi nitions of outcome and exposure were rarely used. Conclusion:
A good study of risk factors for suicidal behaviour would need a high LoE, as a high-powered
longitudinal epidemiological study (cohort or case - control) of very specifi c risk factors. The
factors would have high prevention potential, compared with more broad and unspecifi c risk
factors, to which many people are exposed. We would recommend a cohort design (in high-risk
populations) or a case-control design to identify risk factors, using clinical and/or register data
instead of self-reported information, reporting adjusted estimates and using standard defi nition
of suicidal outcome and risk factors.