Effects of lithium carbonate on associative productivity and idiosyncrasy in bipolar outpatients.

To determine the effect of lithium carbonate on the productivity and idiosyncrasy of written associations of euthymic outpatients with affective disorder, the authors assessed 22 patients at weekly intervals during lithium treatment, 2 consecutive weeks of placebo, and 2 consecutive weeks after lithium was resumed. Lithium discontinuation produced a significant increase in associational productivity and a demonstrable increase in associative idiosyncrasy, and restoration of lithium dose significantly reversed both effects. The results suggest that lithium may affect the underlying neuropsychological functions critical to the ability to generate associations and indicate the need for further study of lithium's effects on these and other functions that may relate to neuropsychological and creative processes.