Lithium response and psychoses: a double-blind, placebo-controlled study.

Lithium-associated remission of psychosis has been described in schizophreniform disorders and in psychotic patients with variants of the red blood cell (RBC)/lithium ratio. To determine whether such remissions are the consequence of lithium treatment rather than spontaneous in nature, a double-blind, placebo-controlled study was undertaken in 16 psychotic patients preselected for the variant of RBC/lithium ration and/or DSM-III schizophreniform diagnosis. Essentially full and sustained remission of psychosis began during periods of lithium treatment in 4 of 15 of the study patients. Improvement was significantly greater during lithium treatment periods than in counterbalanced placebo treatment conditions in these four subjects (p less than 0.02). Fifteen of the same 16 study patients failed to initiate sustained improvement either spontaneously or while on placebo during the initial 14-day treatment period. In this preselected psychotic population, sustained response to lithium occurred at a rate at least four times greater than that which could be attributed to spontaneous remission.