Bipolar Disorders: Mixed States, Rapid-Cycling, and Atypical Forms

26 A. Marneros and F. K. Goodwinboundaries between ‘‘rapid cycling’’ (having at least four episodes in a year) and‘‘not rapid cycling’’ (having fewer than four episodes per year) are in fact arbitrary,although Dunner and Fieve found that most lithium non-responders belonged tothe group of more than four episodes.The subsequent work of Wehr and Goodwin (1979) replicated and extended therapid-cycling findings of Dunner and Fieve, and additionally proposed that antidepressantagents could contribute to the manifestation of rapid cycling. Thisfinding was also later replicated (Calabrese et al., 1991, 1993; see Chapter 3).Calabrese et al. (2000) pointed out:The DSM-IV definition of rapid cycling describes it as a course modifier and is predicated for themost part on the Dunner and Fieve conceptualization of the phenomenon:(1) Four or more episodes of depression, mania, or hypomania in the previous 12 months.(2) Patients need not have an intervening euthymic interval for a mania and a depression to becounted as two episodes.(3) Numbers of episodes were tabulated, rather than numbers of cycles; for example, two cyclesin which manic episodes are biphasically coupled with depressions followed by euthymicintervals would count as four episodes and satisfy criteria for rapid cycling.(4) Episodes are demarcated by a switch to a mood state of opposite polarity or by a period ofrelative remission lasting 2 months (DSM-IV, American Psychiatric Association, 1994).Therefore, consecutive episodes with the same polarity must be separated by a period ofrelative remission lasting 2 months.DSM-IV included rapid cycling as a specifier of longitudinal course, but not as aspecific mood disorder subtype (American Psychiatric Association, 1994). ICD-10(World Health Organization, 1991) did not include any specifier or subgroup‘‘rapid cycling.’’ According to DSM-IV, the specifier ‘‘with rapid cycling’’ can beapplied to bipolar I disorder or bipolar II disorder.The essential feature of a rapid-cycling bipolar disorder is the occurrence of fouror more mood episodes during the previous 12 months. These episodes can occurin any combination and order. The episodes must meet both the duration andsymptom criteria for a major depressive, manic, mixed, or hypomanic episode andmust be demarcated by either a period of full remission or by a switch to an episodeof the opposite polarity. Manic, hypomanic, and mixed episodes are counted asbeing on the same pole (e.g., a manic episode immediately followed by a mixedepisode counts as only one episode = when considering the specifier ‘‘with rapidcycling’’). Except for the fact that they occur more frequently, the episodes that occurin a rapid-cycling pattern are no different from those that occur in a non-rapid-cyclingpattern. Mood episodes that count toward defining a rapid-cycling patternexclude those episodes directly caused by a substance (e.g., cocaine, corticosteroids)or a general medical condition (American Psychiatric Association, 1994).