Trajectories of antidepressant use and 6-year change in body weight: a prospective population-based cohort study

Background: Antidepressant drug treatment may be associated with weight gain, but long-term studies are lacking. Methods: We included 3127 adults (1701 women) from the REGICOR study, on average aged 55.6 (SD=11.6) years in 2003-2006, living in North-East of Spain. They had data at two time points (baseline and a median of 6.3 years later) on self-reported antidepressant use, body weight and height, and on baseline smoking, physical activity, diet quality, education, civil status, and depressive symptoms assessed with the Patient Health Questionnaire (PHQ-9) at follow-up. We defined four trajectories of antidepressants use: never use, new use at follow-up, initial use discontinued, persistent use. We used multivariable linear models to estimate the association of these trajectories with the percentage of weight change. In people without obesity at baseline (n=2404), we also estimated the association with obesity incidence at follow-up. Results: The average 6-year weight gain was 0.53 kg (1.01% body weight), and 24.5% of the participants gained >5% of body weight. The majority (83.6%) of participants did not report any use of antidepressants, 6.2% initiated during follow-up, 5.1% discontinued it, and 5.1% reported their use at both time points. In multivariable analyses, compared to never users, all trajectories were associated with greater weight gain: +1.78% (0.57, 2.98) for initial use discontinued, +2.08% (0.97, 3.19) for new use at follow-up, and +1.98% (95% CI: 0.75, 3.20) for persistent use. In non-obese participants at baseline (n=2404), the odds ratio for becoming obese was 2.06 (1.03, 3.96) for persistent use, and non-statistically significant for the other trajectories. Conclusions: In a population-based adult cohort, persistent use of antidepressants was strongly associated with weight gain. New and discontinued use was associated with weight gain, but non-significantly to obesity incidence. In light of the obesity pandemic, weight management in the context of antidepressant prescriptions is warranted.