Lithium in scalp hair of adults,students, and violent criminals

The lithium content of human hair shows an approximately linear response to extradietary lithium supplementation at dosage levels of up to 2000 μg/d. From the mean hair lithium concentration of 0.063 μg/g in 2648 predominantly American adults, and the reference hair lithium concentrations determined in the present study, the mean lithium intakes were calculated to be 730 μg/d. Hair lithium concentrations were extremely low in nearly 20% of the American samples, and in samples collected in Munich, Germany and Vienna, Austria. Hair lithium levels are low in certain pathological conditions, e.g., heart disease, in learning-disabled subjects, and in incarcerated violent criminals. The highest levels were observed in samples of a lithium-treated psychiatric patient. A statistically highly significant direct association was observed between the hair lithium and cobalt concentrations, which suggests a role of lithium in the transport and distribution of vitamin B₁₂. Interactions of lithium with other trace elements are also discussed.