Antidepressant Use and Circulating Prolactin Levels

Purpose: To determine whether antidepressants (AD), specifically selective serotonin reuptake inhibitors (SSRIs), are linked to elevated prolactin levels among the general population.

Methods: Circulating prolactin levels were available for 4593 healthy participants in the Nurses' Health Study (NHS) and NHS2, including 267 AD users. We fit generalized linear models to calculate and compare adjusted mean prolactin levels between AD users and non-users and further among SSRI users. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for "elevated" prolactin levels (>11 ng/mL) comparing AD users to non-users. We evaluated AD use and change in prolactin levels among 610 NHS participants with two measurements an average of 11 years apart.

Results: Adjusted geometric mean prolactin levels were similar among SSRI users (13.2 ng/mL, 95 % CI 12.2-14.4), users of other classes of ADs (12.7 ng/mL, 95 % CI 11.0-14.6), and non-users (13.1 ng/mL, 95 % CI 12.8-13.4). Neither AD use (OR 1.17, 95 % CI 0.89-1.53) nor SSRI use (OR 0.95, 95 % CI 0.66-1.38) was associated with elevated prolactin levels. Change in prolactin levels was similar across women who started, stopped, consistently used, or never used ADs.

Conclusions: This study does not support the hypothesis that AD use would influence breast cancer risk via altered prolactin levels. These results provide some evidence that use of ADs to treat depression or other conditions may not substantially increase prolactin levels in the majority of women.