Roller-Coasterish Meaning

(idiomatic) Resembling a roller coaster; characterized by abrupt highs and lows.

Example: 1999, Elise Harris, "Writing The Book Of Matthew", Out, March 1999, page 65:
  He had roller-coasterish mood swings and would disappear for a few days at a time, isolating himself, feeling suicidal.
2004, Paul McFedries, Word Spy: The Word Lover's Guide to Modern Culture, Broadway Books (2004), ISBN 9780767914666, page 273:
  Also, the age at which people first get married has had a roller-coasterish ride over the past 100 years or so.
2010, Don Pitcher, Moon Alaska, Avalon Travel (2010), ISBN 9781598803501, page 401:
  The road starts out somewhat roller-coasterish from frost heaves, […]