Social inequalities in suicide: the role of selective serotonin reuptake inhibitors.

We aimed to examine the relationship between socioeconomic status (SES) and suicide associated with the introduction and diffusion of selective serotonin reuptake inhibitors (SSRIs). Negative binomial regression was used to estimate county-level suicide rates among persons aged 25 years or older using death certificate data collated by the National Center for Health Statistics from 1968 to 2009; SES was measured using the decennial US Census. The National Health and Nutrition Examination Survey and the Medical Expenditure Panel Survey were used to measure SSRI use. Once SSRIs became available in 1988, a 1% increase in SSRI usage was associated with a 0.5% lower suicide rate. Prior to the introduction of SSRIs, SES was not related to suicide. However, with each 1% increase in SSRI use, a 1-standard deviation (SD) higher SES was associated with a 0.6% lower suicide rate. In 2009, persons living in counties with SES 1 SD above the national average were 13.6% less likely to commit suicide than those living in counties with SES 1 SD below the national average--a difference of 1.9/100,000 adults aged ≥25 years. Higher SSRI use was associated with lower suicide rates among US residents aged ≥25 years; however, SES inequalities modified the association between SSRI use and suicide.