Lithium remains the gold-standard mood stabiliser for bipolar disorder, yet clinicians have had to infer what it does in the brain from blood tests alone. A Newcastle University study with Technische Universitaet Dresden changes that, using 7Li MRI, a multinuclear imaging technique, to visualise lithium directly in the brains of 41 patients with bipolar disorder, the largest such study yet and the first with repeated measures in this condition.
Patients taking lithium once daily (20 participants) or twice daily (21 participants) each underwent three consecutive scans with matched blood samples over ten hours. At the standard 12-hour post-dose measurement point, the two regimens were indistinguishable in both blood and brain. Brain lithium closely tracked blood lithium across the day, twice-daily dosing produced more stable brain levels, and concentrations were consistently higher in white matter than in grey matter.
Published in The Lancet Psychiatry, the findings matter for everyday prescribing. They support the continued use of blood monitoring as a reasonable proxy for brain exposure, while suggesting that dosing schedules shape the stability of lithium levels in neural tissue. For a drug in clinical use for decades but still incompletely understood, direct brain measurement opens a new route to optimising treatment.