Brain-to-serum lithium ratio and age: an in vivo magnetic resonance spectroscopy study.
OBJECTIVE
The authors' goal was to determine if there is an association between brain-to-serum lithium ratios and age.


METHODS
Lithium-7 magnetic resonance spectroscopy was used to measure in vivo brain lithium levels in nine children and adolescents (mean age=13.4 years, SD=3.6) and 18 adults (mean age=37.3, SD=9.1) with bipolar disorder.


RESULTS
Serum and brain lithium concentrations were positively correlated. Younger subjects had lower brain-to-serum concentration ratios than adults: 0.58 (SD=0.24) versus 0.92 (SD=0.36). The brain-to-serum concentration ratio correlated positively with age.


CONCLUSIONS
These observations suggest that children and adolescents may need higher maintenance serum lithium concentrations than adults to ensure that brain lithium concentrations reach therapeutic levels.
Moore
Constance M
CM
Brain Imaging Center, Consolidated Department of Psychiatry, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA. const@mclean.harvard.edu
Demopulos
Christina M
CM
Henry
Michael E
ME
Steingard
Ronald J
RJ
Zamvil
Linda
L
Katic
Alain
A
Breeze
Janis L
JL
Moore
JoEllyn C
JC
Cohen
Bruce M
BM
Renshaw
Perry F
PF
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001714:Bipolar Disorder / Q000097:blood* / Q000188:drug therapy / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D002648:Child; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008094:Lithium / Q000032:analysis* / Q000097:blood* / Q000627:therapeutic use; D009682:Magnetic Resonance Spectroscopy; D008297:Male
D008094:Lithium