Aims: To assess whether a substantial increase in substance use over a 10-year period has had an impact on the level of, or associations with, non-fatal suicidal behaviour among Norwegian teenagers.
Design, setting and participants: Two cross-sectional school surveys applying identical procedures and measures in 1992 and 2002, using national samples comprising 11 000 and 12 000 13-19-year-old students.
Findings: A significant proportion of the increase in the prevalence of attempted suicide among girls could be attributed to the increase in substance use, taking into account other risk and protective factors. Among boys no net increase in the prevalence of attempted suicide was observed, and the impact of substance use on suicidal behaviour was lower in 2002 than in 1992. Yet, it also appeared that unobserved protective factors may have countered the impact of increased substance use among boys. For both genders a larger fraction of attempted suicides was attributable to alcohol intoxication than to use of any other substance.
Conclusions: A significant increase in use of alcohol and drugs may not necessarily be reflected in changes in the level of suicidal behaviour. Further studies applying other data sources and designs are warranted to supplement and validate the present findings.