Crystals of cocaine viewed through a microscopeASTRID & HANNS-FRIEDER MICHLER/SCIENCE PHOTO LIBRARY An experimental medication targeting reward pathways in the brain helps people addicted to cocaine reduce their drug use – and could treat other substance use disorders, too. Medications are available to treat alcoholism and opioid use disorder, but none are approved for addictions to stimulants such as cocaine and methamphetamine. These drugs contribute to roughly half of all overdose deaths in the US. “So this is a giant unmet medical need,” says Ricardo Dolmetsch, founder of Tempero Bio, a California-based pharmaceutical company. Drugs like cocaine are highly addictive because…