The medication Xanax consists of benzodiazepines which act by increasing the GABA (gamma-aminobutyric acid) neurotransmitter, which blocks the communication between the brain and the nerves—decreasing the abnormal functioning of the brain and changing how the brain feels. The sedative-hypnotics help treat insomnia by slowing down the functioning of the brain and CNS (central nervous system) and providing soothing and relaxation.