Mood-incongruent versus mood-congruent psychosis: Differential antipsychotic response to Lithium therapy

Abstract

The authors previously reported that a subgroup of schizophrenic-like patients respond favorably to lithium (Li) therapy, as do patients with a classical manic illness. In the present study, the time course of psychotic and affective symptom remission after Litherapy was examined in these two groups of patients. Li responsive patients with a mood-incongruent psychosis (schizophrenic-like illness) demonstrated a rapid antipsychotic response to Litheraphy, showing a 50% improvement during the first 7 days, while no improvement in affective symptoms was seen until week 2 or 3 of treatment. Alternatively, patients with a mood-congruent psychosis (where mania is the primary diagnosis) demonstrated no antipsychotic response to Li therapy during the first 2 weeks of treatment, while some improvement in manic symptoms occured during treatment week 2. The present study demonstrates that Li therapy differentially affects psychotic symptoms in mood- incongruent as opposed to mood-congruent psychosis. Further, the growth hormone (GH) response to apomorphine administration differentiated these two groups of Li responsive patients. Patients with a Li responsive mood-incongruent psychosis demonstrated over a seven-fold greater GH response than mood- congruent psychotic patients. The present data suggest that mood-incongruent and mood-congruent psychoses may represent two biologically distinct psychotic processes separable by both medication response and central dopamine function.