Validity of rapid cycling as a course specifier for bipolar disorder.
OBJECTIVE
This study's aim was to test the validity of rapid cycling, defined by criteria consistent with those proposed in the DSM-IV draft, as a course specifier for bipolar disorder.


METHODS
The study was conducted at a university center for affective disorders on patients fulfilling Research Diagnostic Criteria for bipolar disorder. Thirty-seven rapid-cycling patients, i.e., patients with at least four affective episodes during the previous year, were compared with 74 nonrapid-cycling patients on several demographic and clinical variables. All patients were then followed up prospectively for 2-5 years by monthly personal interviews.


RESULTS
The rapid-cycling group was significantly older and had a significantly longer illness duration than the nonrapid-cycling group but did not have a significantly higher percentage of women or frequency of current hypothyroidism. During each year of follow-up, the mean number of affective episodes and the percentage of patients with at least four affective episodes were significantly higher among rapid-cycling patients. Rapid-cycling patients with a pole-switching pattern during the year preceding intake were significantly more likely than other rapid-cycling patients to have at least four affective episodes during each of the first 4 years of follow-up.


CONCLUSIONS
These findings support the practical usefulness of rapid cycling as a course modifier for bipolar disorder, since it identifies a patient subgroup with a high recurrence rate. The predictive value of the modifier may be enhanced by the requirement of a pole-switching pattern. Since no external (i.e., unrelated to course) validator was found, the idea that rapid cycling represents one extreme of a continuum of episode frequency in bipolar disorder remains viable.
Maj
M
M
Department of Psychiatry, First Medical School, University of Naples, Italy.
Magliano
L
L
Pirozzi
R
R
Marasco
C
C
Guarneri
M
M
D000328:Adult; D000367:Age Factors; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012008:Recurrence; D015203:Reproducibility of Results