Antidepressant class, age, and the risk of deliberate self-harm: a propensity score matched cohort study of SSRI and SNRI users in the USA.

BACKGROUND: The US Food and Drug Administration's meta-analyses of placebo-controlled antidepressant trials found approximately twice the rate of suicidal behaviors among children and adults aged 24 years and younger who were randomized to receive antidepressant medication than among those who were randomized to placebo. Rates of suicidal behavior were similar for subjects aged 25-64 years whether they received antidepressants or placebo, and subjects aged 65 years or older randomized to antidepressants were found to have lower rates of suicidal behavior. The age-stratified FDA meta-analyses did not have adequate power to investigate rates of suicidal behaviors by antidepressant drug class.

OBJECTIVE: Our objective was to assess the risk of deliberate self-harm associated with the two most commonly prescribed classes of antidepressant agents.

DESIGN: Propensity score matched cohort study of incident users of antidepressant agents.

SETTING: Population-based healthcare utilization data of US residents.

PATIENTS: US residents aged 10-64 years with a recorded diagnosis of depression who initiated use of selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) between 1 January 1998 and 31 December 2010.

MAIN OUTCOME MEASURES: ICD-9 external cause of injury codes E950.x-E958.x (deliberate self-harm).

RESULTS: A total of 102,647 patients aged between 10 and 24 years, and 338,021 aged between 25 and 64 years, initiated therapy with antidepressants. Among 10-24 year olds, prior to propensity score matching, 75,675 initiated therapy with SSRIs and 5,344 initiated SNRIs. After matching, there were 5,344 SNRI users and 10,688 SSRI users. Among the older cohort, 36,037 SNRI users were matched to 72,028 SSRI users (from an unmatched cohort of 225,952 SSRI initiators). Regardless of age cohort, patients initiating SSRIs and patients initiating SNRIs had similar rates of deliberate self-harm. Restriction to patients with no antidepressant use in the past 3 years did not alter our findings.

CONCLUSIONS: Our findings of similar rates of deliberate self-harm for depressed patients who initiate treatment with either an SSRI or an SNRI suggests that physicians who have decided that their patients would benefit from initiating antidepressant therapy need not weigh differential suicide risk when deciding which class of antidepressant to prescribe.