The term rapid cycling can be very confusing. I recently asked my co-author Dr. John Preston for a clear explanation:
Rapid cycling is at least four discrete episodes during a 12 month period (these can be mania, hypomania, or depression). The term ultra-rapid cycling is not precisely defined but many refer to this as having possibly monthly cycles (e.g. 12 per year)….untradian cycling is where there are not really discrete manic or depressive episodes, but the person is extremely emotionally labile, with chaotic and intense mood changes that occur every day or several times during a day. One way to describe it is that they experience intense emotional instability….some mood shifts are in response to stressful events (e.g. an argument with a friend), but some are unprovoked (seem to come out of the blue and not associated with a specific trigger)
** Thanks John.




