Amygdala and hippocampal volumes in relatives of patients with bipolar disorder: a high-risk study.
OBJECTIVE
Bipolar disorders (BD) have a strong genetic underpinning, yet no biological vulnerability markers for BD have yet been identified. To test whether amygdala or hippocampal volumes represent an endophenotype for BD, we measured mesiotemporal volumes in young affected and unaffected relatives of patients with BD (high-risk design).


METHODS
High-risk participants (aged 15 to 30 years) were recruited from families multiply affected with BD. They included 20 affected and 26 unaffected offspring of parents with primary mood disorders, matched by age and sex with 31 control subjects without a personal or family history of psychiatric disorders. Amygdala and hippocampal volumes were measured on 1.5 Tesla 3-dimensional anatomical magnetic resonance images using standard methods.


RESULTS
We found comparable amygdala and hippocampal volumes among unaffected relatives, affected high-risk patients, and control subjects. The exclusion of 6 medicated patients did not change the results. There were no differences between participants with family history of BD I, compared with participants with family history of BD II, or between subjects with family history of BD with psychotic symptoms, compared with subjects with family history of BD without psychotic symptoms.


CONCLUSIONS
Hippocampal and amygdala volume abnormalities were absent in unaffected and affected relatives of patients with BD and thus did not meet criteria for endophenotype.
Hajek
Tomas
T
Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia.
Gunde
Eva
E
Slaney
Claire
C
Propper
Lukas
L
MacQueen
Glenda
G
Duffy
Anne
A
Alda
Martin
M
D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000473:pathology*; D001714:Bipolar Disorder / Q000473:pathology*; D003430:Cross-Sectional Studies; D005190:Family; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D010641:Phenotype; D012307:Risk Factors; D055815:Young Adult