Presence of rapid cycling appears to be the rule rather that the exception in children with bipolar disorder, although there is not much data to support this clinical notion. Geller and colleagues studied 93 pediatric patients with bipolar disorder, mean age 10.9 years. They found that 87% had rapid cycling defined as ≥4 episodes/year and 77% had ultradian cycling, defined as >365 episodes/year. In addition, Findling and colleagues studied 90 bipolar patients with a mean age of 10.8 years and found that 50% had rapid cycling by veteran CV criteria. (The study did not look at ultra-rapid or ultradian cycling.) Finally, using clinical interviews to study children with affective illness, Schraufnagel and colleagues found that 41% experienced >365 cycles/year (Slide 6).

It is difficult to figure out the difference between a cycle and an episode when children are cycling so quickly. Tillman and Geller proposed that any kind of mood switching constitutes a cycle. An episode, they proposed, is defined as having ≥2 weeks of mood symptoms with either onset and offset of one mood state within that 2 weeks, or onset and offset of a period of ultra-rapid or ultradian cycling. It appears that with younger age comes more rapid cycling and more mixed states, which can be confused with ultra-rapid cycling. In turn, the older the child gets, the less rapid cycling occurs, and the more episodic the disorder becomes with more euphoria and less irritability. However, this tendency has not been well studied.