The six year itch, according to political scientists, is the pattern which takes place during a US president's sixth year in office. This year is characterized by the nation's disgruntled attitude towards the president and his or her political party. During this time, there is a midterm election and the party in power usually loses a significant number of seats in Congress.
Presidents which have faced this curse are as mentioned:
1958- Dwight D. Eisenhower
1974- Richard Nixon (although Gerald Ford was the President when the elections took place that year)
1986- Ronald Reagan
2006- George W. Bush