"The insomnia patients taking the 'relaxation' pills slept really badly, and the patients taking the 'arousal' pills slept much better.
What seemed to be happening was that patients taking 'uppers', normally trapped in a cycle of anxious self-monitoring, could attribute any arousal they had to the pill. Any sign of feeling wired wasn't them, it was the pill, so they could relax and fell asleep easily.
In contrast, those who had taken the 'downers' thought that any arousal must be their insomnia causing them problems, and it must be really bad, because it was getting to them despite the supposed sleeping pill they'd taken. In other words, they were freaking out because they couldn't sleep despite the 'medication'."
The general message is that anxiety causes all kinds of problems, and that anxiety often comes from an improper view of control. If you think you are, or need to be, responsible for everything, you will freak out. But if you accept the situation, and understand the effect of outside factors, you can be more relaxed, and you will end up doing better.