Barbiturates are a group of drugs that are derivates of Barbituric acid. Adolf von Baeyer was the first to produce Barbituric acid, in 1863. For many years, barbiturates were used as sedatives. Today, their use is very limited in many countries, mainly because they cause addiction and people soon develop a tolerance. People with a drug tolerance will need a higher dosage of the drug to get the same effect as before. After a while, the drug becomes useless for such people. This increased use often leads to physical dependence as the body becomes used to the constant presence of barbiturates. When the person abruptly stops taking the drug or reduces the dose, withdrawal symptoms may arise. 