How quickly do mood episodes switch in bipolar disorder with rapid cycling?
Bipolar disorder with rapid cycling is defined by manic/hypomanic, mixed, or depressed episodes (which meet full criteria for such episodes) occurring four or more times in a year.
The concept of ultrarapid cycling (URC) has been proposed to describe episodes alternating every several days or weeks, but URC was not included in the DSM-5.
It is important to reiterate that affective lability/instability (“mood swings” throughout the day or from day to day) alone does not constitute a bipolar mood disorder.
The effects of substances of abuse, personality disorders, or other affect disorders should be considered in the differential of affective lability/instability.
