Medication can be tricky. Two people swallowing the same pill can end up having wildly different outcomes (yay, genetic diversity). Antidepressants are especially notorious for their unpredictability, thanks to the complexity of depression’s underlying pathways. Northwestern University scientists have now discovered that using gene therapy to thwart one of these pathways results in significant reduction of depressive symptoms in mice. The researchers injected a nontoxic virus that expresses a gene meant to stop the production of proteins called HCN channels in the hippocampus. What did they find? No proteins = reduced depressive symptoms. This “straight-to-the-source” therapy has significant implications for the illness—both identifying its genetic underpinnings, and setting the stage for a treatment to help the millions of patients still in search of effective therapies.