A barbiturate is a drug that acts as a central nervous system depressant, and can therefore produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, hypnotics, and anticonvulsants. Barbiturates have addiction potential, both physical and psychological. They have largely been replaced by benzodiazepines in routine medical practice, particularly in the treatment of anxiety and insomnia, due to the significant lower risk of overdose and the lack of an antidote for barbiturate overdose. Despite this, barbiturates are still in use for various purposes: in general anesthesia, epilepsy, treatment of acute migraines or cluster headaches, euthanasia, capital punishment, and assisted suicide.