[A case study of BRON (cough suppressant) tablet dependence--its social psychiatric and biological aspects].

A case of BRON tablet dependence is demonstrated. BRON is an over-the-counter (OTC) cough suppressant, which contains methylephedrine, dihydrocodeine, chlorpheniramine and caffeine. He took BRON tablet for the first time at the age of 16. In progress, he developed psychomotor excitement twice and finally manifested amotivational syndrome 3 years later from his first use. Longitudinal 123I-IMP SPECT (autoradiography method) findings demonstrated diffuse cerebral blood flow (CBF) decrease and relative hyperactivity in the lower frontal lobe. Diffuse decreased regional CBF, which was unchanged through its course for about 4 months, may show irreversible brain damage due to chronic BRON abuse. The findings of relative hyperactivity in the lower frontal lobe (orbitofrontal lobe) may reflect "craving for BRON" based on abnormal dopaminergic neural system activity. Based on the evidence that orbitofrontal hyperactivity is also seen in cases of cocaine abuse, methylephedrine, which is a cocaine-like central nervous system stimulant, may play the main role in BRON dependence formation. In Japan, BRON syrup abuse and dependence were in fashion for youth in 1980s. After the legal regulation of the market in 1988, it has gone out of fashion. While it is still easy to acquire OTC cough suppressant, reports of BRON tablet abuse and dependence are quite rare through 1980s and 1990s. This case suggests that BRON tablet abuse also could lead to dependence and come into new vogue for youth in the future. We should pay attention to the trend of OTC cough suppressant abuse and may need to regulate the market by law more severely.