Lithium Intolerance in a Medical-Psychiatric Population

This pilot study was designed to explore the tolerance and efficacy of lithium as an adjunctive prophylactic agent when added to maintenance antidepressant regimens following an episode of depression in an older medical-psychiatric population. In a randomized controlled trial, 27 depressed patients had either lithium carbonate or placebo added to their maintenance antidepressant (AD) regimen following an index episode of depression. Of 17 patients who received lithium carbonate, 76% (13/17) were unable to tolerate this agent for the duration of the study because of side effects (e.g., gastrointestinal disturbances or tremor). The four patients who tolerated lithium were monitored for relapse of depression over a 15-month follow-up period, and one relapsed (after a 49-week remission), whereas 60% (6/10) of the placebo patients relapsed. Cognitive functioning was stable in the lithium-treated patients who remained on therapy. The high rate of lithium intolerance in this study indicates that lithium dosing and serum levels must be conservatively managed in this clinical population.