SLC5A2 and major depressive disorder: In a conceptually aligned yet pharmacological approach, a Phase 2, six-week, single-group study administers the sodium–glucose cotransporter 2 (SGLT2) inhibitor empagliflozin (10 mg for two weeks then 25 mg for four), targeting adults with moderate MDD (MADRS ≥ 20) and ≤ 2 prior adequate antidepressant failures, and tracks changes in MADRS, suicidality (Columbia-Suicide Severity Rating Scale, C-SSRS), and anhedonia (SHAPS), a design whose open-label architecture and tiny sample (n = 16) nonetheless constrain causal inference (NCT05757791).