Afro-Americans may be more susceptible to the side effects associated with lithium treatment.
Afro-Americans (n=12) had higher Lithium 'RedBloodCount/plasma' ratio (LR) and increased reports of side effects (p < 0.05) compared to Caucasians (n=22). Indicating that among Afro-
Americans intracellular lithiumconcentrations are higher with equal plasma levels.

Strickland et al. 1995.