The effects of an indigenous muscarinic drug, Betel nut (Areca catechu), on the symptoms of schizophrenia: a longitudinal study in Palau, Micronesia.

Objective: This study tested the findings of a prior study indicating a therapeutic relationship between consumption of betel nut and symptoms of schizophrenia.
Method: The subjects were 65 outpatients with diagnoses of schizophrenia or schizoaffective disorder. Symptoms rated with the Positive and Negative Syndrome Scale were compared between high- and low-consumption betel chewers in a repeated-measures design. Movement disorders were assessed with the Abnormal Involuntary Movement Scale and Simpson-Angus Rating Scale. Global health and social functioning were assessed with the Medical Outcomes Study 12-item and 36-item Short-Form Health Surveys, respectively.
Results: Male high-consumption betel chewers had significantly milder positive symptoms than low-consumption chewers over 1 year. Betel chewing was not associated with global health, social functioning, or movement disorders. Betel chewing was associated with tobacco use but not with cannabis or alcohol.
Conclusions: These findings have clinical significance in betel-chewing regions and broader implications for theory of muscarinic neurophysiology in schizophrenia.