Which statement about narcotics is incorrect?

The statement describing narcotics as substances that "intensify vision and increase alertness" is incorrect. Narcotics, which primarily include opium and its derivatives, are known for their analgesic properties, meaning they are effective in relieving pain. They work by binding to specific receptors in the brain and spinal cord, leading to reduced pain perception.

In contrast to enhancing vision or alertness, narcotics often produce drowsiness, sedation, and can impair cognitive and motor functions, making them unsuitable for tasks that require heightened awareness. Their primary clinical uses include pain management and, as mentioned, treatment for conditions like severe diarrhea due to their effect on the gastrointestinal system.

Other statements about narcotics highlight their role in pain relief and reference their origin from opium, both of which are accurate and provide insight into the pharmacological effects and medical uses of these substances.