AAMC FL Practice Exam

What is the primary effect of depressants on the central nervous system?

1. Increases alertness and energy

2. Slows down the central nervous system

3. Enhances perception

4. Stimulates neural pathways

The correct answer is: Slows down the central nervous system

Depressants primarily function by slowing down the central nervous system (CNS). This class of substances, which includes alcohol, benzodiazepines, and opioids, works by enhancing the effects of the neurotransmitter gamma-aminobutyric acid (GABA). GABA is an inhibitory neurotransmitter that, when its activity is enhanced, leads to a calming effect on brain activity. This results in reduced anxiety, sedation, and impaired motor functions, which are characteristic of depressant use. In contrast, other options describe effects that are not associated with depressants. For instance, increasing alertness and energy refers to the action of stimulants, which work by enhancing neural activity and promoting wakefulness. Enhancing perception is often related to hallucinogenic substances, which alter sensory experiences and perceptions. Lastly, stimulating neural pathways is not a function of depressants, as these substances generally inhibit brain activity rather than stimulate it. Thus, the primary effect of depressants is accurately described by the slowing down of the central nervous system, leading to their calming and sedative properties.