Background: Data are scarce on the potential change in suicidal behavior among adolescents and young adults after receiving a cancer diagnosis.
Patients and methods: We conducted a population-based cohort study including 7 860 629 Swedes at the age of ≥15 during 1987-2009. Among the cohort participants, 12 669 received a first diagnosis of primary cancer between the age of 15 and 30. We measured the relative risks (RRs) of suicidal behavior (defined as completed suicides or suicide attempts) after cancer diagnosis. We also carried out a case-crossover study nested within the cohort to adjust for unmeasured confounders.
Results: Twenty-two completed suicides (versus 14 expected) and 136 suicide attempts (versus 80 expected) were identified among the cancer patients. The RR of suicidal behavior was 1.6 [95% confidence interval (CI), 1.4-1.9] after a cancer diagnosis, compared with cancer-free individuals. Risk increase was greatest immediately after diagnosis; the RR was 2.5 (95% CI 1.7-3.5) during the first year after diagnosis and was 1.5 (95% CI 1.2-1.8) thereafter. This pattern was similar for completed suicide and suicide attempts. The elevated risks were evident for majority of the main cancer types, except for cancer in thyroid, testis and melanoma. The case-crossover analysis of suicidal behavior during the first year after cancer diagnosis revealed similar results.
Conclusions: Adolescents and young adults receiving a cancer diagnosis are at substantially increased risk of suicidal behavior, particularly during the first year after diagnosis. Although the absolute excess risk is modest, these findings emphasize the need to support and carefully monitor this vulnerable population.
Keywords: adolescents; cancer diagnosis; psychological stress; suicidal behavior; young adults.