This case report details a 28-year-old woman who developed galactorrhea and hyperprolactinemia after four weeks of treatment with mirtazapine, an atypical antidepressant. Despite initial normal prolactin levels, elevation occurred after 12 days, and symptoms resolved upon switching to escitalopram. The findings suggest that mirtazapine may induce prolactin dysregulation via serotonergic mechanisms, challenging prior assumptions about its minimal impact on prolactin and aligning with growing evidence of antidepressant effects on reproductive hormones. This evidence concerns the gene PRL and Galactorrhea.