The active compound in alcoholic drinks, ethanol, works on two of the brain's most important neurotransmitters, the molecules which transmit signals between networks of neurons. Ethanol increases the effects of gamma aminobutyric acid, the primary neurotransmitter which inhibits neuronal signalling, and suppresses the effects of glutamate, the major excitatory neurotransmitter. The combined impact of these interactions on the brain is to slow neural function, lowering reaction times, worsening cognitive abilities, and enhancing sociability by lowering anxiety and social inhibitions. Consumption of large quantities of alcohol can eventually depress brain activity to the point of unconsciousness or even death, and over a longer period of time, alcohol consumption is associated with a decrease in brain volume.
[P1] Alcohol interacts with the brain to slow neural function.