ACHE and schizophrenia: Further evidence for the Ach hypothesis of VH in schizophrenia comes from findings that high doses of anticholinergic medications can induce a psychotic state [reviewed in Terry (88)], that normal doses of these medications can induce recurrence of psychosis (93), and that acetylcholinesterase inhibitors (which increase the amount of acetylcholine available in the synaptic cleft), used in conjunction with antipsychotic medication, can reduce the frequency of VH (94, 95).