Are There Different Types of Bipolar Disorder?
Researchers and physicians have always commented on the wide variety of forms of bipolar disorder (manic depression). Most people who have bipolar disorder experience episodes of mania–intense highs of energy or euphoria–and periods of depression–extreme lows. The length, frequency, and pattern of episodes varies. Some of these variations may not be scientifically significant, while others are signs of subtypes of bipolar disorder that affect the patient’s experience of the illness and the physician’s approach to treatment.
For instance, patients who experience hypomania, a less sever form of mania with limited impairment; cyclothymia, characterized by numerous, mild manic episodes and often less severe depressive episodes for at least two or more years with no major depressive or manic episode; and rapid cycling, the focus of this booklet.
What is Rapid Cycling?
Rapid cycling is defined as four or more manic, hypomanic, or depressive episodes in any 12-month period. Depressive episodes last two weeks or longer; hypomanic episodes last four days or longer; manic episodes last one week or longer or require hospitalization. However, episodes may be much more frequent and shorter.
While the term “rapid cycling” may lead some people to believe the episodes occur in cycles, they often follow a random pattern. Some patients with rapid cycling appear to experience true manic, mild manic, or depressive episodes that last only for a day. Typically, however, someone who experiences such short mood swings (ultrarapid cycling) has undergone longer episodes as well.
There is an indistinct boundary between rapid cycling and mixed states. Most physicians, however, believe that mixed-state bipolar disorder is distinct from rapid cycling, and do not diagnose rapid cycling unless full-length mood episodes take place.
For some people, rapid cycling is a temporary occurrence. That is, they may experience rapid cycling for a time, then return to a pattern of longer, less frequent episodes. Others, however, may continue in a rapid-cycling pattern indefinitely.
Who Develops Rapid Cycling?
As many as 15-20% of all individuals with bipolar disorder may develop rapid cycling at some time during their illness. Individuals with Bipolar I (those with manic or mixed episodes alternating with major depression) and Bipolar II (those with recurrent major depressive episodes and hypomania) have equal rates of rapid cycling. While there are no absolute rules about who will develop this pattern, up to 90% are women, despite bipolar disorder generally being equally common in both sexes. Several studies have also shown that rapid cycling occurs more frequently in people with bipolar disorder who have evidence of, or history of, hypothyroidism.
Use of antidepressants in bipolar disorder can bring on or worsen rapid cycling, although the cycling often decreases when the antidepressants are discontinued. Therefore, physicians should prescribe antidepressants cautiously.
There may also be a genetic or other physical link between rapid cycling and drug or alcohol abuse. Some studies show that substance abuse is more common in families of those with rapid-cycling bipolar illness than in families of bipolar patients without rapid cycling. Furthermore, a history of substance abuse may make an individual more prone to cycling with episodes that are sorter than usual.
When rapid cycling starts, it typically follows one of these patterns:
- Some individuals experience rapid cycling at the beginning of their illness.
- For others, onset is gradual. Most individuals with bipolar disorder, in fact, experience shorter and more frequent episodes as the illness progresses. Eventually, they may meet criteria for rapid cycling, either temporarily or permanently.
What Causes Rapid Cycling?
The fundamental cause of rapid cycling remains unknown, but three overlapping theories exist:
- Kindling (Sensitization). According to this theory, episodes are initially triggered by actual or anticipated life events such as the death of a loved one or an upcoming job interview. As the sequence is repeated, however, the affected individual becomes increasingly sensitive to anything that may be a trigger. Episodes become increasingly frequent and independent of anything outside the patient’s brain. Sometimes, the result of this process may be rapid cycling.
- Biological Rhythm Disturbances. This theory proposes rapid-cycling patients’ daily biological rhythms are abnormal and out of sync with typical “time-giving” events such as dawn and dusk. This theory could then account for the sleep disturbances typical of mania and depression and explain other symptoms as well. If biological rhythms are important, a link between rapid cycling and seasonal affective disorder (SAD) may be suggested. SAD is a type of depression that typically develops during the fall and winter months and lessens in intensity or completely subsides during the summer months.
- Hypothyroidism. This theory proposes that rapid cycling is due to inadequate amounts of thyroid hormone in the brain. However, most people with rapid cycling have adequate blood levels of thyroid hormone. Nevertheless, low blood levels of thyroid hormone are more common among individuals with rapid cycling than among bipolar patients in general. For this reason, thyroid function tests should be carried out before and during treatment.
Are There Effective Treatments for Rapid Cycling?
While 60% of other individuals with bipolar disorder will obtain some relief from lithium, the response rate among those with rapid cycling is only 20-40%. Lithium’s effectiveness may be reduced by drug or alcohol dependence; however, this relationship does not seem strong enough to account for the great difference in response rates.
The disappointing results obtained with lithium in the treatment of rapid cycling led researchers to seek alternative treatments. When divalproex sodium (Depakote®) was approved in 1995 by the U.S. food and Drug Administration (FDA) for the treatment of mania associated with bipolar disorder, it brought new hope to patients experiencing rapid cycling and mixed states. Carbamazepine (Tegretol®), although not FDA approved as a treatment for bipolar disorder, sometimes is used as a supplement or alternative to divalproex sodium and lithium.
Divalproex sodium and carbamazepine have been effective in treatment of lithium-resistant rapid cycling and mixed state patients. Their effectiveness appears unconnected to their common identity as anticonvulsants used to treat epilepsy. Not only do the individuals they benefit typically show no sign of epilepsy, but some other drugs that are effective as anticonvulsants provide no help in treating bipolar disorder. Further, whether a patient is helped or not helped by one anticonvulsant does not predict whether that same patient will or will not respond to another. Therefore, people with bipolar disorder should not give up hope if their first course of treatment is not successful.
Reasoning that rapid cycling may be due to inadequate thyroid hormone in the brain, several studies have investigated treating rapid-cycling patients with high doses of the thyroid hormone, thyroxine. Despite their small size, these studies have produced favorable results even in individuals without\ a history of thyroid problems.
As noted earlier, antidepressants may trigger rapid cycling. While stopping antidepressant use may seem logical in these situations, the results can be frustrating. A person with bipolar disorder often experiences depression when not taking antidepressant medication. The availability of treatments other than lithium suggests the more complex strategy of adding thyroid hormone or an anticonvulsant to antidepressant therapy may be a more promising approach. The limited data available from studies of thyroid hormone and anticonvulsants suggest this may indeed be the case.
Alternatives to divalproex sodium, lithium and carbamazepine are understudy in rapid cycling. They include another anticonvulsant, lamotrigine (Lamictal®), and an antipsychotic medication, olanzapine (Zyprexa®). These medications are not approved by the FDA for treatment of bipolar disorder, but patients with rapid-cycling illness may want to discuss them with their doctors.
Psychotherapy is an important supplementary treatment to medication. Along with continuous vulnerability to future episodes, people with any type of bipolar disorder experience complications as a result of past episodes. For instance, people who cry easily may be dismissed as weak. People who are always “in a bad mood” may appear less attractive.
Because people with bipolar disorder are often unfairly judged, they may lose opportunities to develop friendships or romantic involvements, or have trouble achieving their career goals. The struggles people with bipolar disorder face may contribute to self-esteem problems. That’s why patients may want to consult their mental health professionals about one-on-one psychotherapy with interpersonal, cognitive or behavioral approaches or the benefits of couples, family, and group therapy.
esearch increasingly suggests that rapid cycling is significantly different from other forms of bipolar disorder. Individuals with this pattern of mood changes may respond differently to standard treatment than others with bipolar disorder.
Rapid cycling, with its sudden and unpredictable mood changes, may be more difficult to cope with than other types of bipolar disorder. This challenge makes it particularly important for patients to work closely with their physicians and/or mental health professionals toward achieving the best results possible.
Progress toward better treatments and the eventual elimination of rapid cycling, and all forms of bipolar disorder, is being made through the cooperation of patients, physicians, clinical researchers, universities, pharmaceutical companies and organizations like National DMDA.