AIMS: To analyse trends in depression diagnoses and antidepressant use according to age and gender.

METHODS: Nationwide cohort study including all women and men of 10-49 years living in Denmark during 2000-2013. The Psychiatric Registry and Prescription Registry provided data on depression diagnoses and antidepressant medication, respectively. Incidence rates as well as 1-year prevalence rates were calculated.

RESULTS: The incidence and 1-year prevalence rates of depression diagnoses increased during 2000-2013. The women/men rates were 2.0 for both 1-year prevalence of depressions diagnoses and antidepressant use. For adolescent girls, the absolute increase was 3 per 1000 for depression diagnoses and 8 per 1000 for first use of antidepressants, compared to boys who had an increase of 1.1 and 3 per 1000, respectively. Before puberty, boys and girls had almost the same incidence rates of both depression diagnoses and antidepressant use throughout the period. After puberty, girls had significantly higher incidence rates than boys, and experienced during the study period a steeper increase than boys. According to age, the girls/boys incidence rate ratio of a depression diagnosis increased from 0.8 in the 10-11 year age group to 2.7 at age 12-19 years and hereafter decreased with increasing age to 1.5 at age 45-49.

CONCLUSIONS: Depression diagnosed and first use of antidepressants increased more for girls of 12-19 years than for boys during 2000-2013, and the incidences were similar for girls and boys before puberty, but higher after puberty for girls.