In the context of bipolar type I or Transtorno bipolar tipo II, there has been a high frequency of mood episodes (at least four) over the past 12 months. There may be a switch from one polarity of mood to the other, or the mood episodes may be demarcated by a period of remissão. In individuals com a high frequency of mood episodes, some may have a shorter duration than those usually observed in bipolar type I or Transtorno bipolar tipo II. In particular, depressive periods may only last several days. If depressive and manic symptoms alternate very rapidly (i.e., from day to day or within the same day), a mixed episódio should be diagnosed rather than rapid cycling.