What is Rapid Cycling?

Most people with bipolar disorder will have between 0.7 and 0.9 episodes of depression or mania per year lasting three to six months. Between episodes euthymia or remission occurs. However there are some who have rapid cycling.

Just as the name suggests rapid cycling is a form of bipolar disorder in which manic and depressive episodes are quite frequent. Specifically it is defined as four or more manic, hypomanic of depressive episodes in any 12 month period. In severe cases mood swings can go back and forth in a matter of days or even hours.

Rapid cycling and ultra-rapid cycling can be difficult to diagnose particularly in those not previously diagnosed with more typical bipolar disorder. Ultra rapid cycling (from day to day) or ultra-ultra rapid cycling (within hours of a day) became used in psychiatric parlance in the ‘90s.
However, people can be misdiagnosed. False positive diagnoses are not uncommon as each high or low does not encompass the usual panoply of symptoms of either alone. The patient may not be bipolar but just have mood lability. Rapid cycling is not a diagnosis in of itself. Symptoms similar to rapid cycling may be distress responses to life changing events. Withdrawal from alcohol or addictive drugs may seem like rapid cycling.

Traumatic brain injury or other brain diseases such as multiple sclerosis or even brain tumors can present with mood lability. PTSD can manifest frequent highs and lows. Even premenstrual and menopausal lability can be mistaken for rapid cycling.

Rapid cycling is the worst manifestation of bipolar disorder and the most disabling. The irritability, anger and impulsivity in particular are disabling and can impact those around the individual. During rapid cycling people are in most danger of suicide and frequently require hospitalization. Peculiarly, people with bipolar II in which the highs are hypomanic are more likely to have episodes of rapid cycling.

The cycles are not in specific sequences of time but rather the cycles occur in random intervals. Half of people with bipolar disorder will in the course of their life-time of their disease have rapid-cycling. Most experience rapid cycling at the first episode and diagnosis of bipolar disorder. Also, individuals already diagnosed with bipolar disorder are more likely to develop rapid cycling if treatment is delayed or not adequately managed.
Rapid cycling is usually temporary and folks will return to a more usual pattern of highs and lows over longer periods of time. Only about 10% will have rapid cycling exclusively and these folks are the hardest to treat and the most recalcitrant to medications. Also, the longer such individuals go without any treatment the more likely they are to become resistant to treatments.
Over treatment with anti-depressants can lead not only to mania or hypomania but can cause rapid cycling. So, mood stabilizers are the preferred treatment for rapid cycling. Finding the right combination of mood stabilizers, usual two, is the challenge facing psychiatrists. Usually lithium combined with an anticonvulsant such as Lamictal is preferred but either combined with an atypical antipsychotic can be required.

Once bipolar depression in rapid cyclers or bipolar patients in general is controlled some psychiatrists think the antidepressant should be tapered off. This and single drug therapy for bipolar disease is very controversial and I personally do not subscribe to this approach.
Some psychiatrists see a correlation between rapid cycling and previous substance abuse or alcohol. Whether there is a genetic link or whether it is acquired by self-medicating is not definitive.
As far as causes of an episode or recurrent episodes there are two trains of thought. First is the concept of kindling or sensitization of early episodes in which there is a trigger event such as loss of a family member, loss of employment, divorce, etc. Over time more minor stressors may lead to rapid cycling. Eventually no trigger may lead to rapid cycling or ultra-rapid cycling.
The second theory is called biological rhythm disturbances. If one’s normal circadian rhythm is disturbed such as rapid change in time zones by air travel with disruption of night versus day cycles mania, in particular, or rapid cycling may occur. This also may be linked to seasonal affective disorder or worsening depression in climates in far northern hemispheres, say above the Arctic Circle. This is another reason insomnia must be adequately controlled and I believe this is the reason a benzodiazepine should be part of the therapy of bipolar disorder. The reason is the commonality of insomnia and anxiety as comorbid conditions with bipolar disease. Insomnia left untreated can mushroom into rapid cycling.

Most people with bipolar disorder do not have hypothyroidism but addition of T4 (Synthroid or its generic) and/or T3 (Cytomel or its generic) may help in refractory bipolar disorder particularly rapid cycling. This should be considered when appropriate.

In summary, not only is rapid cycling the most recalcitrant form of bipolar disorder to treat, but during episodes of rapid cycling, ultra cycling or ultra- ultra rapid cycling people are at most risk of suicide and need intensive drug trial and error often requiring hospitalization.