Addition of lithium to haloperidol in non-affective, antipsychotic non-responsive schizophrenia: a double blind, placebo controlled, parallel design clinical trial.

This double-blind placebo controlled, parallel design clinical trial compared the therapeutic effects of the addition of lithium or placebo to haloperidol in 21 seriously ill state hospital patients with DSM-III-R schizophrenia, who did not have concurrent affective disorders and who had not responded to previous trials of conventional antipsychotic medication. During a baseline period of 6 weeks, patients were switched to a stable dose of haloperidol (mean +/- SD dose = 13.6 +/- 8.1 mg/day). Patients were then randomized to receive either lithium or placebo in addition to haloperidol for 8 weeks (mean +/- SD lithium level = 0.98 +/- 0.13 mEq/l). Symptoms and side effects were assessed weekly. Improvement in symptoms correlated with the non-blind adjustment of antipsychotic dose, but not with lithium or placebo treatment. Side effects ratings did not differ between the two groups, but one patient developed a reversible delirium associated with combined lithium/haloperidol treatment. For these long-term, severely ill patients, combined treatment afforded no advantage over treatment with haloperidol alone.