Cohort study reveals age-specific risks for childhood and adolescent mental disorders

A nationwide population-based cohort study published in JAMA Psychiatry has reported the “first comprehensive assessment” of the incidence and risks of mental disorders in childhood and adolescence.

“For many mental disorders, we believe we have identified age- and sex-specific patterns of occurrence that, to our knowledge, have not been previously reported,” Søren Dalsgaard, MD, PhD, of the Lundbeck Foundation Initiative for Integrative Psychiatric Research in Denmark, and colleagues wrote. “The distinct signatures of the different mental disorders with respect to sex and age may have important implications for service planning and etiological research.”

The researchers included all 1.3 million individuals born in Denmark from 1995 through 2016. They used criteria from the ICD-10 to determine incidence rates and cumulative incidences for all participants diagnosed before age 18 years during the study period.

Among the study population, 99,926 individuals (15.01%; 95% CI, 14.98-15.17) were diagnosed with a mental disorder before age 18 years. Among girls, anxiety disorder was the most common diagnosis (7.85%; 95% CI, 7.74-7.97), and ADHD was the most common in boys (5.9%; 95% CI, 5.76-6.03). The risks for schizophrenia, obsessive-compulsive disorder and mood disorders were higher for girls than for boys. Incidence peaked significantly earlier in boys than in girls in ADHD (8 years vs. 17 years), intellectual disability (5 years vs. 14 years) and other developmental disorders (5 years vs. 16 years). The overall risk for mental disorder diagnosis before age 6 years was 2.13% (95% CI, 2.11-2.16) and was higher in boys (2.78%; 95% CI, 2.44-3.15) than in girls (1.45%; 95% CI, 1.42-1.49).

“Knowledge of the age-specific risks for mental disorders forms the backbone for public health decisions, prioritization of resources, evidence-based medicine and research on risk factors and outcomes,” the researchers wrote. – by Joe Gramigna

Disclosures: Dalsgaard reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.