Valium works by enhancing the activity of a neurotransmitter called GABA (gamma-aminobutyric acid), which has a calming effect on the brain and nervous system. By increasing GABA activity, Valium can reduce anxiety, muscle spasms, and seizures. That said, long-term abuse of Valium can alter the brain’s chemistry and structure, leading to changes in mood, behavior, and cognitive function. Chronic Valium use can also lead to tolerance, dependence, and addiction, which can further alter brain function and increase the risk of withdrawal symptoms and relapse.