Many scientific studies have suggested that taking melatonin tablets can induce sleep. But this does not mean that me...

shunhe on January 11, 2020

Hi @Hunter,

Thanks for the question! This is a Strengthen question, so we need new information in the answer choice to help boost the stimulus. The stimulus tells us that even though melatonin tablets can induce sleep, it’s not necessarily true that it helps treat insomnia. As evidence, it shows that studies that show melatonin helps sleep don’t study people with insomnia, and people aren’t affected by it that much anyway. We need something that helps bolster the claim that melatonin won’t help insomnia. (C) gives us this. (C) tells us that when subjects with insomnia were included (since “most” of the studies examined only people without insomnia), only the ones without insomnia were significantly affected by the melatonin. That means that the people with insomnia weren’t significantly affected by it, which suggests that the melatonin isn’t helpful in treating insomnia. You’re right that it would be different if the stimulus says “melatonin doesn’t affect people with insomnia,” which would be a stronger argument. But the argument isn’t that. It’s actually that melatonin isn’t helpful in treating insomnia. If the melatonin doesn’t significantly affect someone with insomnia, maybe only helping them sleep an extra 2 or 3 minutes, we wouldn’t say that it’s helpful in treating insomnia. Hope this helps! Feel free to ask any further questions you might have.