PURPOSE: On March 1st 2009, restrictions on the dispensing of selective serotonin reuptake inhibitors (SSRI) in Iceland were lifted. Incident rates and changes in early discontinuation and switching before and after the change were investigated.

METHODS: New users of antidepressants between March 1st 2006 and March 1st 2010 were selected from the Icelandic Prescriptions Database. The study population was split into one intervention cohort (2009) and three comparison cohorts (2006, 2007, and 2008). Incidence rate ratios (IRR) and odds ratios (OR) were used to compare incidence rates and early discontinuation.

RESULTS: The overall incidence rates of antidepressant use decreased from 33.10 to 28.71 per 1000 persons per year (IRR 0.87; 95% confidence interval (CI), 0.78-0.97) from the 2006 to the 2009 cohort. The incidence rate for SSRIs did not change over the period. Early discontinuation for SSRIs increased from 30.2% in 2006 to 34.1% in 2009 (OR 1.19; 95% CI 1.06-1.33).

CONCLUSIONS: The change in reimbursement does not seem to have affected incidence rates but it may be related to increased early discontinuation, which can lead to increased drug wastage. It might be more clinically rational to initiate patients on smaller supply, allowing for more frequent check-up visits.