SSRI Treatment Failure: Contemporary Mechanisms, Diagnostic Pitfalls, and Evidence-Based Next Steps (2021–2025 Update)

I. López-Ibor, MD ABSTRACT Selective serotonin reuptake inhibitors (SSRIs) remain first-line pharmacological treatment for major depressive disorder (MDD). However, real-world remission rates remain modest, and “treatment failure” is frequently misclassified (1). Contemporary evidence highlights that non-response is often driven by diagnostic error, inadequate dosing/duration, pharmacokin...