The effect of episodes on recurrence in affective disorder: a case register study.
BACKGROUND
The risk of recurrence has been found to increase with the number of episodes in both unipolar and bipolar affective disorder. The present study compared the effect of the number of episodes on the risk of recurrence in the two disorders.


METHODS
A case register study including all hospital admissions with primary affective disorder in Denmark during 1971-1993. The effect of the number of prior episodes on the rate of recurrence following the first discharge after 1984 was estimated. A total of 7925 unipolar patients and 2011 bipolar patients were included in the study.


RESULTS
The rate of recurrence was, on average, 1.6 times greater for bipolar patients than for unipolar patients. Nevertheless, the effect of the number of episodes was greatest for unipolar patients. Thus, the rate of recurrence increased, on average, 15% with every episode for unipolar patients and 9% with every episode for bipolar patients, when adjusted for differences in age and gender.


CONCLUSIONS
The risk of recurrence increases with every new episode in affective disorder. The effect of episodes is greater for unipolar disorder than for bipolar disorder.


CONCLUSIONS
The data relate to re-admissions rather than recurrence.


CONCLUSIONS
The study shows that the prognosis worsens more for unipolar than for bipolar patients with each new episode and suggests the relevance of earlier and more sustained intervention.
Department of Psychiatry, University of Copenhagen, Rigshospitalet, Denmark. lars.kessing@dadlnet.dk
L V
LV
Kessing
P K
PK
Andersen
D000368:Aged; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000534:rehabilitation*; D003718:Denmark / Q000453:epidemiology; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000534:rehabilitation*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D010343:Patient Admission / Q000706:statistics & numerical data; D011379:Prognosis; D011569:Psychiatric Status Rating Scales; D012008:Recurrence; D012042:Registries; D012189:Retrospective Studies