As Americans gear up to celebrate Halloween at the end of October, a recent survey has revealed the fears that really keep people up at night. The Chapman University Survey of American Fears polled 1,207 U.S. adults on their levels of fear across 80 different categories. Like last year, corruption of government officials came top in 2017, with 74.5 percent of U.S. adults saying it makes them "afraid" or "very afraid".The unrest and uncertainty of Donald Trump's presidency has had a significant influence on this year's ranking. With the U.S. health system still engulfed by chaos, 55.3 percent of respondents are fearful of the American Healthcare Act/Trumpcare. The president's decision to withdraw from the Paris Climate Accords has also had an impact with 48 percent afraid of global warming and climate change and 44.9 percent fearful of air pollution.The threat of war between the U.S. and North Korea is also starting to touch a nerve. 48.4 percent of Americans fear U.S. involvement in another world war while 47.5 percent are afraid the regime in Pyongyang will use nuclear weapons.