The Scottish Comorbidity Study Group has highlighted again the problem of greater use of drugs and alcohol, and especially tobacco, among patients with schizophrenia (McCreadie et al, 2002). An underrecognised comorbidity, however, especially in developing countries, is that of chewing betel nut (Areca catechu), along with the betel leaf (Piper betle) and lime.

In a preliminary study conducted in the North Colombo Teaching Hospital, Sri Lanka, we observed that a higher proportion of patients with schizophrenia chewed betel compared with control subjects. The frequency of chewing betel was also higher among the patients with schizophrenia. A recent study from Micronesia (Reference Sullivan, Allen and OttoSullivan et al, 2000) has shown that betel chewing may in fact have a beneficial effect on patients with schizophrenia in terms of reducing both positive and negative symptoms. They postulate that the muscarinic agonist action of the betel nut alkaloid, arecoline, may provide an explanation.

However, betel chewing is an important risk factor for oro-pharyngeal carcinoma, and contributes significantly to oral health-related morbidity and mortality (Reference Trivedy, Craig and WarnakulasuriyaTrivedy et al, 2002). Thus, the dual diagnosis of schizophrenia and betel chewing should not be missed, and services to address this problem should receive priority in many developing countries.