Which type of drug is known for slowing down brain activity?

Depressants are the class of drugs that slow down brain activity, leading to a calming effect on the central nervous system. These substances work by enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA), which reduces neuronal excitability. This slowing of brain activity can result in relaxation, decreased anxiety, and sedation, which are common reasons people use depressants, particularly in the contexts of managing anxiety, sleep disorders, or for recreational use.

Stimulants, on the other hand, have the opposite effect by increasing brain activity and enhancing alertness and energy levels. Hallucinogens primarily alter perception, mood, and cognitive processes but do not inherently slow down brain activity. While psychoactive drugs encompass a broader category that affects the mind, not all psychoactive drugs act to depress brain function; they can include stimulants and hallucinogens as well. Therefore, the best choice reflecting the action of slowing down brain activity is depressants.