Anergic depression accompanied by increased intracellular sodium and lithium

This report describes a patient who experienced chronic retarded depression punctuated by precipitous worsening of mood with hyperphagia or by intermittent euphoric episodes. Ratings of depressive symptom severity changed in close association with intracellular sodium content. Intracellular sodium was highly correlated with intracellular lithium. Difficulties that were encountered in the clinical management of this patient are discussed.