Abstract:
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. Betel nut (Areca catechu) is ubiquitously chewed by millions of people from East Africa to the Pacific and is the fourth most widely used drug worldwide after caffeine, nicotine, and alcohol (1). Arecoline, the principal betel alkaloid (2), is a potent nonselective muscarinic agonist (3, 4). Several associations have been drawn between the pathophysiology of schizophrenia and muscarinic neurotransmission, including evidence for pathology of muscarinic receptors in people with schizophrenia (5), evidence that muscarinic agonists are efficacious in animal behavioral models of schizophrenia (6) and human clinical studies (7), and evidence of neurochemical interactions between dopaminergic and muscarinic neural systems (6). The results from a previously conducted cross-sectional pilot study in Palau, Micronesia, are suggestive of a therapeutic relationship between consumption of betel nut and the symptoms of schizophrenia (8, 9). The aim of the current research was to test the pilot study findings with a longitudinal research design in the same setting.