By 1980, primidone was seen as not worth mentioning as an option for childhood temporal lobe epilepsy by doctors in the United Kingdom. In January 1981, Dr. O'Brien and colleagues reported that primidone had a positive effect on the essential tremor of one of their patients. This led them to initiate a twenty-person prospective study. Twelve of the participants responded well. By 1984, valproic acid was the drug of choice for juvenile myoclonic epilepsy and not the equally effective primidone. However, as late as 1985, primidone was still one of the most widely used anticonvulsants. At the close of the 1980s, primidone was still the preferred anticonvulsant for complex partial seizures in Germany. In 1989, Dainippon Pharmaceutical launched Exegran (zonisamide), the first new, chemically unique, non-benzodiazepine anticonvulsant in decades.