Carbamazepine was approved in the United States for the treatment of adult epilepsy in 1974. Its lack of sedating properties relative to phenobarbital and lack of somatic effects relative to phenytoin generated much interest. Within two years, primidone was no longer seen as the drug of choice for psychomotor epilepsy in the United States. This was because while carbamazepine and primidone are of roughly equal effectiveness, the former is less likely to cause sedation and cognitive impairment. Also, primidone has a greater tendency to cause undesirable psychiatric side effects compared with carbamazepine, which was noted to "lessen" pre-existing depressive symptoms. By 1978, it looked as if its superior side effect profile would increase its use in epilepsy in the United States. That same year, a review was published stating that primidone and phenobarbital were used less often in the United Kingdom due to their greater tendency to cause behavior disorders and interfere with learning in young children. Valproate was heralded by some as "the greatest thing since Greta Garbo" and carbamazepine had also risen in popularity.