Erythrocyte electrolytes in recurrent affective disorders.

A modified method for determination of erythrocyte electrolytes is presented. The claims which have been made regarding the predictive value in periodic psychoses of erythrocyte electrolytes and 'lithium index' are questioned. Clinical experimental data of serial studies in patients receiving lithium suggests that theoretical predictions of distribution of lithium across erythrocyte membranes are not supported in practice and this lends support to the suggestion of active lithium transport in the red cell. A simple method is described of determining the attainment of 'stable state' in long term lithium treatment.