Youth depression diagnosis associated with increased risk for somatic diseases, mortality

Individuals diagnosed with depression during their youth were at increased risk for numerous somatic diseases, as well as for mortality, according to results of a population-based cohort study published in JAMA Psychiatry.

“To date, most large observational studies have focused on adult populations,” Marica Leone, BSc, of Janssen Pharmaceutical Companies of Johnson & Johnson in Sweden, and colleagues wrote. “The extent to which depression diagnosed at a young age differs from adult-onset depression in terms of somatic morbidities, sex-specific patterns and mortality has rarely been explored.”

Further, the researchers noted it is unclear whether early-onset depression is significantly linked to specific diseases and premature death and whether these links remain after controlling for psychiatric comorbidity. Leone and colleagues sought to address this research gap by quantifying the association between youth depression and subsequent diagnoses of somatic diseases and mortality. They analyzed Swedish national registry data of nearly 1.5 million individuals born in Sweden between 1982 and 1996, with follow-up from age 5 years through 2013 if no censoring occurred. One diagnosis of depression from inpatient or outpatient care between ages 5 and 19 years signified youth depression. Specifically, the researchers evaluated 69 somatic conditions diagnosed after youth depression, as well as cause-specific and all-cause mortalities.

Results showed 37,185 (2.5%) participants had an inpatient or outpatient contact for depression between ages 5 and 19 years. Those with youth depression were at higher relative risks for 66 of 69 somatic diagnoses, with strong associations for certain injuries, particularly self-harm among females (HR = 14.4; 95% CI, 13.8-15.1), as well as sleep disorders (HR = 8.1; 95% CI, 7.6-8.7), viral hepatitis (HR = 6.1; 95% CI, 5.4-6.8), all-cause mortality (HR = 5.9; 95% CI, 5.3-6.6) and cause specific mortalities, particularly death by intentional self-harm (HR = 14.6; 95% CI, 12.6-16.9). The researchers noted that most associations were attenuated but persisted after psychiatric comorbidity adjustment. The range of absolute risk difference of a specific disease within 12 years of the first diagnosis of depression was 0.2% (95% CI, 1.0% to 0.6%) for arthropathies among males to 23.9% (95% CI, 22.7%-25.0%) for injuries among females.

“More research is needed to identify whether depression at a young age leads to adverse health outcomes or common causes underlie both,” Leone and colleagues wrote. “Discovery of disease mechanisms that may serve as intervention targets in early life should be prioritized in light of the substantial disease burden associated with youth depression diagnoses.”