Sl. Mcelroy et al., Axis I psychiatric comorbidity and its relationship to historical illness variables in 288 patients with bipolar disorder, AM J PSYCHI, 158(3), 2001, pp. 420-426
Objective: Bipolar disorder often co-occurs with other axis I disorders, bu
t little is known about the relationships between the clinical features of
bipolar illness and these comorbid conditions. Therefore, the authors asses
sed comorbid lifetime and current axis I disorders in 288 patients with bip
olar disorder and the relationships of these comorbid disorders to selected
demographic and historical illness variables.
Method: They evaluated 288 outpatients with bipolar I or II disorder, using
structured diagnostic interviews and clinician-administered and self-rated
questionnaires to determine the diagnosis of bipolar disorder, comorbid ax
is I disorder diagnoses, and demographic and historical illness characteris
tics.
Results: One hundred eighty-seven (65%) of the patients with bipolar disord
er also met DSM-IV criteria for at least one comorbid lifetime axis I disor
der. More patients had comorbid anxiety disorders (N=78, 42%) and substance
use disorders (N=78, 42%) than had eating disorders (N=9, 5%). There were
no differences in comorbidity between patients with bipolar I and bipolar I
I disorder. Both lifetime axis I comorbidity and current axis I comorbidity
were associated with earlier age at onset of affective symptoms and syndro
mal bipolar disorder. Current axis I comorbidity was associated with a hist
ory of development of both cycle acceleration and more severe episodes over
time.
Conclusions: Patients with bipolar disorder often have comorbid anxiety, su
bstance use, and, to a lesser extent, eating disorders. Moreover, axis I co
morbidity, especially current comorbidity, may be associated with an earlie
r age at onset and worsening course of bipolar illness. Further research in
to the prognostic and treatment response implications of axis I comorbidity
in bipolar disorder is important and is in progress.