Which CNS depressant produces a sense of calm and reduces nervousness, excitability, and irritability without causing sleep unless given at a large enough dose?

• A. Sedatives
• B. Hypnotics
• C. Barbiturates
• D. Stimulants

Answer: (D)

The main idea here is how different CNS drugs affect arousal and anxiety. The description matches sedatives: these agents calm and reduce nervousness and irritability without necessarily causing sleep at standard doses. They lower CNS arousal so a person feels more relaxed, but sleep only tends to occur at higher doses. Hypnotics are designed to induce sleep and do so at typical doses, so they’re not the best fit for feeling calm without sleep. Stimulants, by contrast, increase CNS activity, enhancing alertness and energy rather than producing calm. Barbiturates can act as either sedatives or hypnotics depending on the dose, but the characterization given points most directly to a general sedative effect.