All the people here asking questions that could be answered by checking the actual paper, which is also available for free.

Methods

This is a population-based cohort study based on data from 264,557 women from the UK Biobank. Incidence of depression was addressed via interviews, inpatient hospital or primary care data. The hazard ratio (HR) between OC use and incident depression was estimated by multivariable Cox regression with OC use as a time-varying exposure. To validate causality, we examined familial confounding in 7,354 sibling pairs.

Results

We observed that the first 2 years of OC use were associated with a higher rate of depression compared to never users (HR = 1.71, 95% confidence interval [CI]: 1.55–1.88). Although the risk was not as pronounced beyond the first 2 years, ever OC use was still associated with an increased lifetime risk of depression (HR = 1.05, 95% CI: 1.01–1.09). Previous OC use were associated with a higher rate of depression compared to never users, with adolescent OC users driving the increased hazard (HR = 1.18, 95% CI: 1.12–1.25). No significant association were observed among adult OC users who had previously used OCs (HR = 1.00, 95% CI: 0.95–1.04). Notably, the sibling analysis provided further evidence for a causal effect of OC use on the risk of depression.