Physostigmine and lithium response in the schizophrenias.

Conflicting reports concerning cholinomimetic-induced reduction of schizophrenic symptoms prompted the authors to study such changes in schizophrenic symptoms following physostigmine infusions in subgroups of patients with schizophrenic-like illness. These subgroups were defined by the presence or absence of antipsychotic response during a 2-week trial of lithium alone after physostigmine infusion. Patients who showed significant but temporary improvement in their thinking disturbance on serial Brief Psychiatric Rating Scale scores following physostigmine infusion subsequently responded to lithium; patients who failed to improve following physostigmine also failed to respond to lithium. The authors suggest that some schizophrenic-like illnesses may be biologically similar to mania both with respect to physostigmine and lithium-induced changes in symptomatology.