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

20 A. Marneros and F. K. GoodwinFrequencyThere are no systematic epidemiological studies on mixed states. The estimationof their frequency is mainly based on studies of psychiatric inpatients and, to alesser extent, outpatients. Going back to Kraepelin, it has always been clear thattheir frequency is dependent on the definition applied. Thus, Kraepelin (1899),as well as Weygandt (1899), estimated that by applying broad definitions, theirfrequency is very high: approximately 60%. Applying a narrow definition,which requires the full symptomatology of melancholia and of mania, reducesthe frequency to about 20%. Thus, contemporary reviews of the prevalence ratesof mixed states in patients with bipolar disorder report a range between 5 and70% (Goodwin and Jamison, 1990; McElroyet al., 2000). With a median ofabout 43% (Goodwin and Jamison, 1990), exactly the same percentage wasfound in the Cologne study (Marneros et al., 1991a, b). Further, the Colognestudy observed bipolar patients over 25 years and noted that only 1% of thepatients consistently had mixed states (Marneros et al., 1991a, b). It seems thatthe frequency of mixed states is related to the duration of the illness, and thepredominance of manic or depressive phases. Thus, the longer the duration ofthe illness, the greater the possibility of mixed states. Additionally, theHABILOS showed with regard to the ratio of manic to depressive episodesthat the more manic the course, the greater the possibility of mixed states (seeChapter 9). The frequency of mixed states has been reported to be higher amongfemales; although this finding is controversial (Marneros et al., 1991a, b;McElroy et al., 1992, 1995; Akiskalet al., 1998; Arnoldet al., 2000). Somestudies suggested that mixed states are not uncommon in childhood andadolescence (Geller and Luby, 1997; McElroy et al ., 1997) (see Chapter 10).PhenomenologyThe classical work of Kraepelin (1899, 1913, 1921) and of Weygandt (1899)provided a rich and fascinating description of mixed states. Modern studiesconfirm the observations of the classical literature that depressive symptoms arecommon in mania and hypomania (Kotin and Goodwin, 1972), and vice versa:manic features can also occur in depression (Himmelhoch, 1979; Koukopouloset al., 1992, 1995, 2000; Bauer et al., 1994; Perugi, et al., 1997; Akiskal et al., 1998;Cassidy et al., 1998a, b; Dilsaver et al., 1999; see Chapter 7). Contemporary databasedstudies provide support for conceptualized mixed states broadly and dimensionally,as well as categorically (McElroy et al., 2000). However, one has to beaware that the broader the definition, the greater its shortcomings.In addition to a mixture of manic and depressive symptoms, mixed states arealso frequently characterized by anxiety, suicidal tendencies, and catatonic andpsychotic symptoms (Kraepelin, 1899, 1913; Weygandt, 1899; McElroy et al., 2000;