Cyclothymia is a rare mood-related condition. It causes emotional ups and downs, but they are not as extreme as those in bipolar disorder. With cyclothymia, you will experience periods in which your mood shifts significantly from very good to very bad compared to your baseline. You may feel on top of the world for a while, followed by a short period when you feel somewhat down. Between these cyclothymic highs and lows, you can feel well and stable.