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A Selective Association between Central and Peripheral Lithium Levels in Remitters in Bipolar Depression: A 3T‐ 7 Li Magnetic Resonance Spectroscopy Study
Author(s) -
MachadoVieira R.,
Otaduy M. C.,
Zanetti M. V.,
De Sousa R. T.,
Dias V. V.,
Leite C. C.,
Forlenza O. V.,
Busatto G. F.,
Soares J. C.,
Gattaz W. F.
Publication year - 2016
Publication title -
acta psychiatrica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.849
H-Index - 146
eISSN - 1600-0447
pISSN - 0001-690X
DOI - 10.1111/acps.12511
Subject(s) - lithium (medication) , bipolar disorder , medicine , antidepressant , depression (economics) , adverse effect , pharmacokinetics , psychology , gastroenterology , endocrinology , hippocampus , economics , macroeconomics
Objective The objective of this study was to evaluate brain lithium levels using 7 Li magnetic resonance spectroscopy after 6 weeks of lithium therapy in bipolar depression to test the hypothesis that brain and plasma lithium are correlated. It was also tested whether responders and remitters have different pharmacokinetics, blood and brain lithium levels (ratio) compared with those presenting suboptimal antidepressant improvement. Method Twenty‐three patients with bipolar disorder (I and II ) during depressive episodes were included and followed up for 6 weeks at the University of Sao Paulo using flexible dose of lithium (450–900 mg/day). Sixteen patients were drug‐naïve. At endpoint, patients underwent a 7 Li‐ MRS scan and brain lithium concentrations were calculated. Results A significant association between central and peripheral lithium levels was found only in remitters ( r = 0.7, P = 0.004) but not in non‐remitters ( r = −0.12, P = 0.76). Also, brain lithium (but not plasma) was inversely correlated with age ( r = −0.46, P = 0.025). Plasma lithium did not correlate with any clinical outcome, lithium dosage or adverse effects. Conclusion These findings suggest that non‐remitters may not transport lithium properly to the brain, which may underlie treatment resistance to lithium in BD . Future studies with 7 Li‐ MRS integrated with the evaluation of blood–brain barrier transport mechanisms and longitudinal clinical outcomes in BD and aging are warranted.