Gender by onset age interaction may characterize distinct phenotypic subgroups in bipolar patients.
OBJECTIVE
Although bipolar disorder (BD) is a common recurrent condition with highly heterogeneous illness course, data are limited regarding clinical implications of interactions between gender and onset age. We assessed relationships between onset age and demographic/illness characteristics among BD patients stratified by gender.


METHODS
Demographic and unfavorable illness characteristics, descriptive traits, and clinical correlates were compared in 502 patients from Stanford University BD Clinic patients enrolled in the Systematic Treatment Enhancement Program for BD between 2000 and 2011, stratified by gender, across pre-, peri-, and post-pubertal (<12, 13-16, and >17 years, respectively) onset-age subgroups.


RESULTS
Among 502 BD patients, 58.2% were female, of whom 21.9% had pre-pubertal, 30.7% peri-pubertal, and 47.4% post-pubertal onset. Between genders, although demographics, descriptive characteristics, and most clinical correlates were statistically similar, there were distinctive onset-age related patterns of unfavorable illness characteristics. Among females, rates of 6/8 primary unfavorable illness characteristics were significantly higher in pre-pubertal and peri-pubertal compared to post-pubertal onset patients. However, among males, rates of only 3/8 unfavorable illness characteristics were significantly higher in only pre-pubertal versus post-pubertal onset patients, and none between peri-pubertal versus post-pubertal onset patients.


LIMITATIONS
Caucasian, insured, suburban, American specialty clinic-referred sample limits generalizability, onset age based on retrospective recall.


DISCUSSION
We describe different phenotypic presentations across age at illness onset groups according to gender. Among females and males, peri-pubertal and post-pubertal onset age groups were more different and more similar, respectively. Further investigation is warranted to assess implications of gender-by-onset-age interactions to more accurately delineate distinctive BD phenotypes.
['Holtzman|Jessica N|JN|', 'Miller|Shefali|S|', 'Hooshmand|Farnaz|F|', 'Wang|Po W|PW|', 'Chang|Kiki D|KD|', 'Goffin|Kathryn C|KC|', 'Hill|Shelley J|SJ|', 'Ketter|Terence A|TA|', 'Rasgon|Natalie L|NL|']
D000328:Adult D017668:Age of Onset D001714:Bipolar Disorder D016009:Chi-Square Distribution D005260:Female D006801:Humans D008137:Longitudinal Studies D008297:Male D008875:Middle Aged D010641:Phenotype D011569:Psychiatric Status Rating Scales D012111:Residence Characteristics D012189:Retrospective Studies D012727:Sex Characteristics
Gender Onset age Bipolar disorder Illness course Clinical comorbidity Early onset