Please click below for the survey results, 18 people completed the survey in 24 hours with a variation of answers. When most people are jittery they are also nervous, the main concerns were unknown situations, pressure and fear of relationships and social situations, and phobias such as heights and spiders. 61% of the people asked felt a lot of pressure can make them feel jittery, and no physical substance makes most people jittery. The two films most people found scariest were The Ring and The Exorcist, so this maybe a place to look into how they create that scary feeling.
I have found the use of this survey definitely an excellent resource of information and inspiration. The next stage is to research into the most popular answers and then to come up with initial ideas.