Social position and antidepressant dose trajectories: a latent class analysis of a french cohort linked to the reimbursement register.

PURPOSE: Antidepressant (AD) doses may vary depending on symptom severity over time. Individuals in lower social positions experience more severe and recurrent depressive episodes, yet it remains unclear whether and how their AD dosage reflects this higher burden. This study aimed to identify AD dose trajectories in a population-based sample and examine their associations with social position indicators.

METHODS

We used data from the French CONSTANCES cohort linked to the national drug reimbursement register. We included incident AD users who initiated a selective serotonin reuptake inhibitor or a selective norepinephrine reuptake inhibitor during their cohort inclusion year. We adopted a Latent Class Mixed Modeling framework to identify AD daily dose trajectories, adjusting for severity proxies. Multinomial regression models assessed the association between trajectory membership and baseline social position indicators.

RESULTS

Overall, 4520 participants (63% women) were included. Four latent AD trajectories were identified: a "Constant" class including most participants (94%) characterized by stable dosing around 20 mg fluoxetine-equivalents; and three classes smaller classes showing varying patterns: a "High-decreasing" class (3.5%), a "High-sharp-decrease" class (1.32%), and "Low-slight-increase" (1.16%). In terms of social position, participants living in the most deprived areas were more likely to follow the 'High-decreasing' class than the 'Constant' one, while participants living alone were more likely to belong to the "High-sharp-decrease" class compared to the "Constant".

CONCLUSIONS

AD dose trajectories showed little heterogeneity with most users following a stable dosing pattern and only small groups displaying fluctuating patterns. Social position influence may be more prominent in determining AD initiation than in shaping dose patterns over time.