Background: Mental health service use has increased among the young.Trends in psychiatric hospitalizations might lend clues as to underlying causes influencing young peoples’ growing use ofpsychiatric services.

Methods: We calculated population-adjusted rates for seven broadcategories of ICD-10 psychiatric diagnoses for Swedishinpatients discharged 1997- 2011. We computed rates forages 13-74 overall, as well as six age strata: 13-17, 18-24, 25-29,30-44, 45-64 and 65-74 years, utilizing data from nationalregisters.

Results: The overall population-standardized rate of psychiatric hospitalizations did not change significantly over the 15-year period. Yet, children and young adults under age 30 sawnotable increases in inpatient psychiatric care, with ratesroughly doubling over the time period. Affective and anxietydisorders accounted for much of these increases, with curvi-linear increases in developmental and childhood behavioral disorders. Rates among older age groups were more stable,though all age groups saw increases in hospitalizations for anxiety disorders. Declines were seen for adults ages 30-44 for psychotic disorders. Adults ages 65-74 declined in hospitalizations for affective disorders while rising for all other age groupsduring this time.

Conclusions: Young adults ages 18-29 years have become the age group withthe greatest proportion hospitalized for psychiatric care. Adolescents and young adults under age 30 saw rises in ratesof psychiatric inpatient care, while at the same time, older age groups did not. A large portion of this increase is due to affective and anxiety disorders, warranting investigation into changes in outpatient care practices, severity, or perceivedseverity of these disorders among this age group.