Brain Lithium Concentrations Mirror Serum Concentrations in Bipolar Disorder

FRIDAY, July 10, 2026 (HealthDay News) — For euthymic individuals with bipolar disorder receiving stable lithium carbonate treatment, brain lithium levels closely match blood lithium levels and are more stable with twice-daily dosing, according to a study published online June 28 in The Lancet Psychiatry.

Philipp Ritter, M.D., Ph.D., from Technische Universität Dresden in Germany, and colleagues examined whether brain lithium profiles differed across the day with once- versus twice-daily dosing regimens in a repeated-measures, cross-sectional imaging study, involving 41 euthymic individuals with bipolar disorder type I or II receiving stable lithium carbonate treatment. Participants received lithium at 2000 hours (full once-daily dose or evening dose of twice-daily regimen) and 0800 (twice-daily regimen only) in the week before assessment (20 individuals receiving once-daily dosing; 21 individuals receiving twice-daily dosing). The core assessment comprised a one-day protocol in which participants underwent three consecutive ⁷Li magnetic resonance imaging (MRI) scans and matched serum sampling over 10 hours.

The researchers found that brain ⁷Li MRI signal intensity and serum lithium concentrations were equivalent across the regimens at 12 hours postdose. Serum lithium declined across the day in the once-daily group, while it increased after the morning dose, then decreased in the twice-daily group. These regimen-specific serum profiles were closely mirrored by brain ⁷Li MRI signal intensity.

“This study shows that lithium MRI is a powerful tool for studying how the drug interacts with the brain and could support more personalized treatment in future,” coauthor David A. Cousins, M.B.B.S., from Tyne and Wear NHS Foundation Trust in the United Kingdom, said in a statement.

One author disclosed ties to Philips Healthcare.

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