Trends in prevalence of depression in Germany between 2009 and 2017 based on nationwide ambulatory claims data

Background: Studies based on health insurance funds unanimously indicate a rise in administrative prevalence of depression, while population surveys with standardized diagnostic procedures do not. We describe recent trends in the prevalence of depressive disorders as diagnosed in routine care from 2009-2017 in Germany. Methods: We used nationwide ambulatory claims data from all residents with statutory health insurance, covering 87% of the total population. Cases were defined as persons with at least one documented diagnosis of depression (ICD-10-GM codes: F32, F33 or F34.1). The administrative prevalence was computed for each year according to age, sex, degree of urbanization and severity of depression diagnosis. Results: The prevalence increased from 12.5% in 2009 to 15.7% in 2017 (+ 26%). Overall, women were twice as likely as men to receive a diagnosis, although the prevalence increased more strongly in men compared to women (+ 40% vs. + 20%). Age- and sex-stratified analyses revealed the highest prevalence increase in adolescents and young men at the ages of 15-19 years (+ 95%) and 20-25 years (+ 72%). Rural areas with a low population density showed the highest rise in administrative prevalence (+ 34%), while big urban municipalities showed the lowest (+ 25%). Limitations: Administrative claims data rely on diagnoses coded for billing purposes and thus depend on coding practice as well as patients' help seeking behavior. Conclusions: Depressive disorders are of increasing importance in ambulatory health care in Germany. Parts of the increase may be attributed to changing cultural constructions of mental health along with the expansion of mental health care supply.