CNS depressants primarily affect which part of the body?

CNS depressants are substances that primarily act on the central nervous system to produce a calming effect, which is why the correct answer is the central nervous system itself. These substances, such as alcohol, benzodiazepines, and barbiturates, slow down brain activity. As a result, individuals may experience effects such as reduced anxiety, sedation, and impaired cognitive and motor functions.

The central nervous system encompasses the brain and spinal cord, which are crucial for processing information, regulating bodily functions, and coordinating actions. By affecting this system, CNS depressants can lead to decreased alertness, slower reflexes, and heavier sedation, demonstrating their specific impact on cognitive and physical responses.

While the other options highlight different bodily systems, they do not capture the primary action of CNS depressants. For instance, while there can be cognitive effects from using CNS depressants, the essence of their impact is more directly related to their action on the central nervous system itself.