Central nervous system (CNS) depressants are a class of drugs that slow brain activity by reducing neuronal excitability, producing calming, sedative, anxiolytic, muscle-relaxant, or sleep-inducing effects. They act primarily by enhancing inhibitory neurotransmission, often through the gamma-aminobutyric acid (GABA) system. CNS depressants are commonly prescribed to treat conditions such as anxiety, insomnia, seizures, and muscle spasms, but excessive use or misuse can lead to drowsiness, impaired coordination, respiratory depression, dependence, and overdose.