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

332 J. Cookson and S. Ghalibbeing investigated, but as yet no clear phenomenological association with mixedstates has been reported.It has been reported that mania occurring in later life (after the age of 65) ismore likely to present in mixed episodes (Shulman and Post, 1980), but this hasnot been confirmed. The situation in people with a first presentation of mania inolder age is being researched in detail. A study based on Danish national caseregisters found that the diagnosis of dementia was associated with an increased riskof both depression and mania over subsequent years compared with controlgroups with osteoarthritis or diabetes (Nilsson et al., 2002).Ultrarapid cyclingOperationally mixed states may be defined in terms of the coexistence of symptomsof both mania and depression in sufficient numbers or at sufficient levels ofseverity. It should be noted that DSM-IV and Tenth Revision of InternationalClassification of Disease (ICD-10: World Health Organization, 1993) differ somewhatin their definitions of mixed states. ICD-10 includes patients showing amixture or alternation of manic and depressive symptoms for 2 weeks. Thiswould include people who might otherwise be classified as having rapid-cyclingbipolar disorder. DSM-IV requires full mania and full depression for 1 week.Rapid cycling is included as a course specifier of bipolar disorders in DSM-IV(American Psychiatric Association, 1994), and defined as ‘‘at least four episodes ofa mood disturbance in the previous 12 months that meet criteria for manicepisode, a hypomanic episode, or a major depressive episode.’’ Episodes aredemarcated by either partial or full remission for at least 2 months, or a switchto a mood state of opposite polarity.Ultrarapid cycling describes four or more episodes a month. Recently, ultradiancycling has been described in otherwise typical bipolar patients; mood changes insuch patients occur in a matter of minutes or hours (Kramlinger and Post, 1996).Perugi et al.(2000), reporting on 320 bipolar patients, have shown that bipolarillness with depression at onset is significantly more likely than manic and mixedstates onset to develop rapid cycling, suicidal behavior, and psychotic symptoms.This study confirmed that rapid cycling was distinct from mixed states. However,in ultrarapid cycling ( 4 episodes/month) there may be considerable overlap withmixed states.Patients with ultradian cycling can also be found among those with a diagnosisof borderline personality disorder, but these also present with extensive difficultiesin maintaining relationships. Their treatment poses unusual difficulties.Antidepressant response to valproate in rapid-cycling patients was associatedwith absence of borderline personality disorder (Calabrese et al., 1993).