Neighbourhood Material and Social Deprivation and Exposure to Antidepressant Drug Treatment: A Cohort Study Using Administrative Data

Objective: To assess whether neighbourhood deprivation is associated with exposure to an antidepressant drug treatment (ADT) and its quality among individuals diagnosed with unipolar depression and insured by the Quebec public drug plan. Method: We conducted an administrative database cohort study of adults covered by the Quebec public drug plan who were diagnosed with a new episode of unipolar depression. We assessed material and social deprivation using an area-based index. We considered exposure to an ADT as having ≥1 claim for an ADT within the 365 days following depression diagnosis. Among those exposed to ADT, ADT quality was assessed with 3 indicators: first-line recommended ADT, persistence with the ADT, and compliance with the ADT. Generalized linear models were used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (95% CI). Results: Of 100,432 individuals with unipolar depression, 65,436 (65%) were exposed to an ADT in the year following the diagnosis. Individuals living in the most materially deprived areas were slightly more likely to be exposed to an ADT than those living in the least deprived areas (aPR, 1.04; 95% CI, 1.03 to 1.06). The likelihoods of being exposed to a first-line ADT, persisting for the minimum recommended duration and complying with the ADT were independent of the deprivation levels. Conclusions: Neighbourhood deprivation was not associated with ADT quality among individuals insured by the Quebec public drug plan. It might be partly attributable to the public drug plan whose goal is to provide equitable access to prescription drugs regardless of income.