Ultra-rapid cycling bipolar disorder: A critical look
Key factors help differentiate mood shifts in BD from other types of affective lability
Ultra-rapid cycling (URC) entered the psychiatric lexicon in the 1990s as a proposed descriptor for manic/hypomanic, mixed, or depressed episodes of bipolar disorder (BD) that occur every few days or weeks. DSM-IV-TR incorporates rapid cycling (RC)—but not URC—as a course specifier that occurs in 10% to 15% of patients with BD who have ≥4 distinct affective episodes per year, each fulfilling duration criteria and separated by identifiable recovery periods (unless an episode directly changes polarity). Since then, the terms RC and URC have seemingly metamorphosed into imprecise, popular colloquialisms meant to loosely describe frequent mood changes rather than distinct episodes over extended time periods, with little regard for the associated signs that define manic or hypomanic episodes.
This article examines the meaning and validity of URC in BD, its relevance and differentiation from rapid mood shifts in patients without BD, and concepts relevant to treatment extrapolated from studies of RC BD.
Post et al1 coined the terms “ultra-rapid cycling” and “ultra-ultra-rapid cycling” (also called “ultradian cycling”) to describe mood episodes that occur monthly (URC) or over the course of as little as 1 day (ultradian cycling). These constructs are controversial because they lack demonstrated content validity and discriminant validity relative to other disorders. (“Content validity” refers to whether the features thought to comprise an entity of interest accurately and meaningfully do so; “discriminant validity” tells researchers and clinicians whether the proposed description of a clinical entity uniquely differentiates it from other disorders—avoiding “false-positive” suspected cases.) Clinicians therefore must pay careful attention to non-bipolar psychiatric problems that can present with rapid mood changes but without the psychomotor and related signs that define bipolar mood episodes. In their looser, nontechnical meanings, “rapid cycling” or “ultra-rapid cycling” may be synonymous with affective lability. RC is neither a diagnosis in itself nor a criterion for diagnosing BD. Rather, it is a course specifier to describe episode frequency in patients with past unambiguous manic or hypomanic episodes.
In children and adolescents, whose presentations often are atypical and can be hard to differentiate from other forms of behavioral or temperamental dysregulation, severe non-episodic mood dysregulation without signs of mania or hypomania may indicate a phenomenon separate from BD.2 Geller and colleagues3 proposed using the term “episodes” to frame the duration of a DSM-IV-defined syndrome of mania/hypomania or depression, while reserving the term “cycling” to connote patterns of mood alternation within a given episode. It is not clear whether this concept of “cycling” differs qualitatively from mood lability that arises during a mood episode in children or adults, and notably, this perspective does not account for changes in psychomotor signs in conjunction with changes in mood.
Clinicians also sometimes blur the concept of “mixed episodes” with RC or URC. DSM-IV-TR defines mixed episodes within bipolar I disorder (BD I) based on criteria for a simultaneous manic and depressive episode, rather than on frequent oscillations between affective poles. These and other differential diagnostic considerations for suspected URC are summarized in Table 1.4
A further concern regarding nomenclature involves the distinction between cyclicity (ie, successive episodes regardless of pole direction) and changes in polarity (ie, switches from depression to mania/hypomania or vice versa). Some mood disorder patients may have rapid oscillations from euthymia to depression while never changing polarity to mania/hypomania and may be best described as having recurrent brief depression.
Differential diagnosis in suspected URC
Considerations for assessment
Mixed episodes in bipolar I disorder, or mixed depressive episodes in bipolar II disorder
DSM-IV-TR mixed episodes entail the co-occurrence of manic and depressive symptoms during the same episode without an intervening period of recovery. ICD-10 includes “rapid alternation of manic, hypomanic or depressive symptoms…from day to day or even hour to hour” in its definition of a mixed episode
Distress responses to acute environmental adversities (eg, adjustment disorders with mixed disturbance of emotions and conduct)
One would expect an absence of corresponding sleep-wake cycle changes or speech-language and psychomotor disturbances
Intoxication/withdrawal from psychoactive substances or drug-induced mental status changes (eg, corticosteroids, amphetamine, cocaine); a history of substance abuse also may be associated with development of URC in BD patients4
Substance-induced mood fluctuations caused by intoxication/withdrawal can mimic affective cycling
Disinhibition states and frontal lobe syndromes as seen in traumatic brain injury and other CNS disorders, such as multiple sclerosis
Assess for signs of perseveration and history of head trauma or neurologic damage from cumulative toxic-metabolic insults (eg, chronic alcoholism)
Autonomic hyperarousal, emotional volatility, and hyperreactivity to environmental stresses, suggestive of PTSD
Determine the presence of a trauma history and review whether DSM-IV-TR symptoms and associated features of PTSD exist, including re-experiencing/reliving and avoidance, as well as paranoid thinking, dissociation, and nightmares
Recurrent mood shifts related to premenstrual dysphoric disorder may mimic URC. Other endocrine dysfunctions also may present with URC (eg, thyroid or ovarian malignancies)
Affirm the independent presence of BD before inferring its manifestations solely from premenstrual mood changes
Trait affective instability associated with borderline personality disorder
Trait mood instability is more chronic and enduring than episodic, and would not be expected to occur in tandem with signs of psychomotor activation that define mania/hypomania
BD: bipolar disorder; ICD-10: International Statistical Classification of Diseases and Related Health Problems, 10th revision; PTSD: posttraumatic stress disorder; URC: ultra-rapid cycling
Clinicians and researchers have debated the minimum duration criteria for identifying manic or hypomanic episodes, and the extent to which suspected hypomanic periods of short duration constitute distinct illness phases. Although DSM-IV-TR designates 4 days as a minimum time for classifying an episode of hypomania, empirical studies suggest that mood symptoms lasting as few as 2 days may comprise a valid and reliably distinct entity relevant to RC.5 More limited data (mainly case observations) identify “affective oscillations” and “mood shifts” occurring faster than once per 24 hours in BD patients without comorbid personality disorders.6 Phenomenologic studies that have focused on 24- to 48-hour switch cycles have described new-onset URC arising spontaneously or following closed head injuries.7 In children and younger adolescents, reports have identified long index manic episodes (mean durations as long as 80 weeks)8 that involve continual (ultradian) mood cycling in as many as 80% of cases.9
Is URC a valid construct?
A central controversy surrounding the validity and meaningfulness of URC as a BD subtype involves its sole focus on mood variation rather than the fuller constellation of associated signs and symptoms that define episodes of mania/hypomania or depression. Abrupt, sudden, drastic, or dramatic mood shifts from one moment to the next are nowhere to be found in the DSM-IV-TR definition of BD, and the construct of mood lability or affective instability is neither a cardinal nor defining element of BD. Although individuals with BD I or bipolar II disorder (BD II) may have periods of affective lability, rapid shifts in mood are neither necessary nor sufficient for a BD diagnosis, and may indicate other types of psychopathology when affective instability occurs in the absence of a history of discernible manic or hypomanic episodes.
Studies by our group10 and others11 have shown that overattention to mood variation without considering associated cognitive, speech-language, chronobiologic, and motor signs of mania/hypomania accounts for substantial overdiagnosis of BD in patients with non-specific mood disturbances, particularly in those with active substance abuse or borderline personality disorder (BPD). Whereas the construct of RC BD attempts to account for changes in energy and psychomotor function as part of recurrent syndromes of mania/hypomania, existing literature on URC does not. Assessing mood changes in <24 hours also precludes assessing associated phenomena that occur over longer periods, such as changes in the sleep-wake cycle.
A rigorous, systematic approach to differential diagnosis for patients with affective instability is essential.
Borderline personality disorder
A common diagnostic debate regarding URC involves how to differentiate it from the chronic mood instability and reactivity inherent to BPD. Although some authors have suggested that RC BD and affective instability in BPD may be the same entity,12 others object to unifying the 2 conditions without considering their phenomenologic and other clinical differences. For example, affective instability arising from borderline character organization is thought to reflect a patient’s impaired capacity to self-regulate his or her internal state and emotional responses to interpersonal and other environmental stresses, or difficulty managing impulses. By contrast, manic or depressive phases of BD tend not to be “triggered” by interpersonal conflicts or frustrations. Furthermore, reframing intense mood reactions to the environment as bipolar variants carries several pitfalls: doing so wrongly accords patients a passive role in their reactions to life events, inaccurately reinforces a sense of victimization in response to stress, and diverts inquiry away from a patient’s active role in life decisions and circumstances that may be unsatisfying, self-defeating, or volatile.
Two key considerations may be helpful in discriminating rapid mood changes in BD vs BPD. First, some longitudinal studies indicate that RC often is a transient, rather than enduring, phenomenon in BD,13 in contrast to the nonvarying, trait feature of affective instability in persons with BPD. It is unknown whether URC is more enduring than transient. Notably, whereas bipolar mood episodes constitute deviations from a baseline state, affective instability in BPD is a baseline characteristic, rather than a deviation from it. Second, by definition, a BPD diagnosis hinges on additional elements unrelated to mood disturbances, such as interpersonal styles or defense mechanisms that involve splitting, projection, and projective identification, feelings of numbness, boredom, or emptiness, identity diffusion, fears of abandonment, and proclivities toward self-mutilation or other self-injurious behaviors as a means to alleviate tension and stress. These characteristics do not overlap with the core elements of BD.
Affective lability in patients with BPD entails prominent oscillations between anger and anxiety, or depression and anxiety, but not depression and elation14; by contrast, affective instability in BD has been linked with greater oscillations between euthymia and depression, and euthymia and elation, but not euthymia and anger.15 Moreover, daily mood fluctuations in patients with BD appear to occur in a relatively random fashion,16 whereas in BPD mood fluctuations are reactions that appear intimately linked to distressing interpersonal experiences.
See the table below, entitled “Rapid cycling and ultra-rapid cycling BD: A comparison,” comparing the phenomenology of RC and URC and a discussion of studies that explored genetic markers or family patterns that may be related to RC or URC.
No systematic studies exist for treating URC. Because most clinical trials of BD focus on treatment or prevention of a single episode rather than changes of mood over time, it is difficult to draw inferences about the ability of any treatment to attenuate marked, day-to-day mood variations. Some antimanic drugs, such as carbamazepine, have been suggested to offer better prophylactic efficacy compared with lithium for “non-classical” BD presentations, although the efficacy of carbamazepine has not been studied in URC.
Broadly speaking, treatment for URC, similar to RC, pragmatically involves:
- identifying and eliminating sources of mood destabilization (eg, substance abuse, erratic sleep patterns)
- treating medical comorbidities such as hypothyroidism
- optimizing treatment with mood stabilizing agents
- exercising caution when using antidepressants (see below).
Interestingly, despite frequent allusion to certain medications as “mood stabilizers,” no controlled study has examined mood instability on a day-to-day basis as a primary outcome measure in BD treatment, which limits the ability to surmise that any drug could be expected to diminish mood oscillations that occur over the course of days, or within a single day. However, a post hoc analysis by our group17 compared randomized treatment with lamotrigine or placebo over 6 months in RC BD I or BD II. Using prospective life charting, we found patients who received lamotrigine were almost twice as likely as those receiving placebo to achieve euthymia from one week to the next, which suggests the possibility that lamotrigine may offer benefit for affective instability in BD I or BD II patients, in addition to preventing discrete mood episodes.