Depressive disorders in adolescence, recurrence in early adulthood, and healthcare usage in mid-adulthood: A longitudinal cost-of-illness study.

Background: Depression in adolescence is associated with increased healthcare consumption in adulthood, but prior research has not recognized the heterogeneity of depressive disorders. This paper investigated the additional healthcare usage and related costs in mid-adulthood for individuals with adolescent depression, and examined the mediating role of subsequent depression in early adulthood.

Methods: This study was based on the Uppsala Longitudinal Adolescent Depression Study, initiated in Sweden in the early 1990s. Depressive disorders were assessed in adolescence (age 16-17) and early adulthood (age 19-30). Healthcare usage and related costs in mid-adulthood (age 31-40) were estimated using nationwide population-based registries. Participants with specific subtypes of adolescent depression (n = 306) were compared with matched non-depressed peers (n = 213).

Results: Women with persistent depressive disorder (PDD) in adolescence utilized significantly more healthcare resources in mid-adulthood. The association was not limited to psychiatric care, and remained after adjustment for individual and parental characteristics. The total additional annual cost for a single age group of females with a history of PDD at a population level was estimated at 3.10 million USD. Depression recurrence in early adulthood mediated the added costs for psychiatric care, but not for somatic care.

Limitations: Primary health care data were not available, presumably resulting in an underestimation of the true healthcare consumption. Estimates for males had limited precision due to a relatively small male proportion.

Conclusions: On a population level, the additional healthcare costs incurred in mid-adulthood in females with a history of adolescent PDD are considerable. Early treatment and prevention should be prioritized.