Pituitary volumes in relatives of bipolar patients: high-risk study.
BACKGROUND
Increased, decreased, as well as unchanged pituitary volumes have been reported in bipolar disorders (BD). It is unclear, whether abnormal pituitary volumes increase vulnerability for BD (primary vulnerability marker), or are secondary to burden of illness. To address this question, we performed the first high-risk study of pituitary volumes in affected and unaffected relatives of bipolar subjects.


METHODS
High-risk participants (age range 15-30 years) were recruited from families multiply affected with BD and included 24 unaffected, 19 affected subjects with first or second degree bipolar I or II relative, matched by age and sex with 31 controls without a personal or family history of psychiatric disorders. Pituitary volumes were measured on 1.5 T 3D anatomical MRI images using standard methods.


RESULTS
We found comparable pituitary volumes among unaffected, affected relatives of bipolar patients and controls. There were no differences in pituitary volumes between male and female subjects nor was there any sex by group interaction. Analyzing 26 participants with bipolar I parent or excluding 5 medicated subjects did not change the results. There were no differences between subjects from families containing bipolar I versus families containing only bipolar II subjects.


CONCLUSIONS
The lack of abnormalities in unaffected and also affected subjects early in the course of illness in our study, as well as previous investigations of bipolar and familial unipolar children and adolescents, suggest that pituitary volume abnormalities are unlikely to be a primary risk factor for mood disorders.
Hajek
Tomas
T
Department of Psychiatry, Dalhousie University, Room 3089, QEII HSC, A.J. Lane Bldg 5909 Veteran's Memorial Lane, B3H 2E2, Halifax, NS, Canada.
Gunde
Eva
E
Bernier
Denise
D
Slaney
Claire
C
Propper
Lukas
L
Macqueen
Glenda
G
Duffy
Anne
A
Alda
Martin
M
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000235:genetics; D016241:Child of Impaired Parents; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005190:Family; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010902:Pituitary Gland / Q000473:pathology*; D012307:Risk Factors; D055815:Young Adult