Mixed hypomania in 908 patients with bipolar disorder evaluated prospectively in the Stanley Foundation Bipolar Treatment Network: a sex-specific phenomenon.
BACKGROUND
The prevalence of depressive symptoms co-occurring with hypomanic symptoms has not been quantified. Whether there is a greater likelihood for women to experience mixed symptoms has not been resolved.


OBJECTIVE
To determine whether mixed hypomania is observed more frequently than euphoric hypomania and whether a sex effect exists in patients with bipolar disorder.


METHODS
Academic research settings in the United States (4 sites) and Europe (3 sites).


METHODS
Subjects were enrolled in a naturalistic prospective study after providing written informed consent.


METHODS
Mixed hypomania was defined at a given visit as a Young Mania Rating Scale score of 12 or higher and an Inventory of Depressive Symptomatology-Clinician-Rated Version score of 15 or higher. Given partial overlap of items from these scales, exploratory analyses were completed assessing instrument overlap affecting the findings.


RESULTS
In 908 patients, 14 328 visits over 7 years were evaluated. Patients with bipolar I disorder were significantly more likely to experience hypomania than those with bipolar II disorder. Of all 1044 visits by patients with hypomanic symptoms, 57% met criteria for mixed hypomania. The likelihood of depression was significantly greater for women during hypomania (P<.001). For women, the probability of mixed symptoms increased with the severity of hypomania and then decreased at the most severe levels of hypomania or mania. When a modified Inventory of Depressive Symptomatology-Clinician-Rated Version was evaluated by removing the 5 overlapping Young Mania Rating Scale items, a significant sex effect persisted for women (P<.001) but not for men (P = .95), owing to the elimination of the items "irritability" and "agitation."


CONCLUSIONS
Mixed hypomania is common in patients with symptoms of hypomania and particularly common in women. Potential overlap of clinical symptom scales should be assessed before study of patients with bipolar disorder symptoms is undertaken.
Suppes
Trisha
T
Bipolar Disorder Research Program, Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas 75390-9121, USA. trisha.suppes@utsouthwestern.edu
Mintz
Jim
J
McElroy
Susan L
SL
Altshuler
Lori L
LL
Kupka
Ralph W
RW
Frye
Mark A
MA
Keck
Paul E
PE
Nolen
Willem A
WA
Leverich
Gabriele S
GS
Grunze
Heinz
H
Rush
A John
AJ
Post
Robert M
RM
D000328:Adult; D000553:Ambulatory Care; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D005060:Europe / Q000453:epidemiology; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010555:Personality Inventory / Q000706:statistics & numerical data; D015995:Prevalence; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D012720:Severity of Illness Index; D017678:Sex Distribution; D012737:Sex Factors; D014481:United States / Q000453:epidemiology