Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness?

Morphine is the main opium alkaloid that depresses the respiratory center and contributes to the fall in blood pressure. Valium is a benzodiazepine (sedative) that gives a feeling of relaxation, calmness, or drowsiness in the body. Amphetamines are synthetic drugs and are stimulants in nature. Hashish is a hallucinogen. Therefore, the correct answer is Valium.