Purpose: To compare the cumulative incidence of mental disorders among adolescents and young adults (AYAs) diagnosed with cancer with the general population and their unaffected siblings.
Methods: A retrospective, population-based, matched cohort design was used to investigate the impact of cancer diagnosis on mental disorders among individuals age 15-39 diagnosed between 1989 and 2019. Two cancer-free cohorts were identified: matched population-based and sibling cohorts. Outcomes included incidence of mood and anxiety disorders, substance use disorders, suicide outcomes, psychotic disorders, and any of the preceding four categories within 5 years of cancer diagnosis. Competing risk regression was used to estimate adjusted subhazard ratios (aSHR) and 95% CIs.
Results: Among 3,818 AYAs with cancer matched to the population-based cancer-free cohort, individuals with cancer were more likely to be diagnosed with incident mental disorders than those without cancer; the risk was highest immediately after a cancer diagnosis and decreased over time with aSHR [95% CI] for mood and anxiety disorders at 0-6 months (11.27 [95% CI, 6.69 to 18.97]), 6-12 months (2.35 [95% CI, 1.54 to 3.58]), and 12-24 months (2.06 [95% CI, 1.55 to 2.75]); for substance use disorders at 0-6 months (2.73 [95% CI, 1.90 to 3.92]); for psychotic disorders at 0-6 months (4.69 [95% CI, 2.07 to 10.65]); and for any mental disorder at 0-6 months (4.46 [95% CI, 3.41 to 5.85]), 6-12 months (1.56 [95% CI, 1.14 to 2.14]), and 12-24 months (1.7 [95% CI, 1.36 to 2.13]) postcancer diagnosis. In sibling comparison, cancer diagnosis was associated with a higher incidence of mood and anxiety and any mental disorder during first 6 months of cancer diagnosis.
Conclusion: AYAs with cancer experience a greater incidence of mental disorders after cancer diagnosis relative to population-based and sibling cohorts without cancer, primarily within first 2 years, underscoring the need to address mental health concerns during this period.