Hormonal contraceptives seem to increase the risk of depression, particularly among adolescents, according to JAMA Psychiatry. The Danish study followed 1,061,997 women aged 15 to 34 years (mean 24.4 years) for, on average, 6.4 years.

About half (55.5 per cent) used hormonal contraception. The rates of first use of anti-depressants and diagnosis of depression at a psychiatric hospital were 2.2 and 0.3 per 100 person years respectively in those who used hormonal contraceptives, compared with 1.7 and 0.28 respectively in non-users.

Compared with non-users, women who took combined oral contraceptives and progestogen-only pills were 23 and 34 per cent more likely to need antidepressants for the first time. The risk doubled among those using norgestrolmin patches (relative risk [RR] 2.0) and was 60 and 40 per cent higher in users of etonogestrel vaginal rings and levonorgestrel intrauterine systems respectively.

Adolescents were at particularly high risk. For example, females aged 15-19 years taking combined oral contraceptives (RR 1.8) and progestogen-only pills (RR 2.2) were about twice as likely as non-users to start anti-depressants. “Healthcare professionals should be aware of this relatively hitherto unnoticed adverse effect of hormonal contraception,” the authors conclude.

^{doi:10.1001/ jamapsychiatry.2016.2387}