2.2 Cohort of older people treated with SSRIs
Using the longitudinal dataset, we selected a cohort of patients aged ≥65 years with at least two prescriptions of SSRIs between January 1, 2000, and December 31, 2013, in order to avoid inclusion of patients who never took the medication in their first prescription. For each patient, the date of cohort entry was defined as the date of his or her first prescription. SSRI drugs, including fluoxetine, citalopram, paroxetine, sertraline, fluvoxamine, and escitalopram, were proven by The Food and Drug Administration to be effective in treating adulthood depression. The Anatomical Therapeutic Chemical classification system and the Defined Daily Dose (DDD) system were adopted to standardize the potencies of different inhibitors (Table S2)[22].