CNS Depressant FAQs

How do CNS depressants affect the brain and body?

Most CNS depressants act on the brain by increasing activity at receptors for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Although the different classes of CNS depressants work in unique ways, it is through their ability to increase GABA signaling—thereby increasing inhibition of brain activity—that they produce a drowsy or calming effect that is medically beneficial to those suffering from anxiety or sleep disorders.

What are the possible consequences of CNS depressant misuse?

Despite their beneficial therapeutic effects, benzodiazepines and barbiturates have the potential for misuse and should be used only as prescribed. The use of non-benzodiazepine sleep aids, or z-drugs, is less well-studied, but certain indicators have raised concern about their misuse potential as well.

During the first few days of taking a depressant, a person usually feels sleepy and uncoordinated, but as the body becomes accustomed to the effects of the drug and tolerance develops, these side effects begin to disappear.

If one uses these drugs long-term, he or she may need larger doses to achieve the therapeutic effects. Continued use can also lead to dependence and withdrawal when use is abruptly reduced or stopped (see Understanding Dependence, Addiction, and Tolerance).

What are the symptoms of CNS depressant withdrawal?

Because CNS depressants work by slowing the brain’s activity, when an individual stops taking them, there can be a rebound effect, resulting in seizures or other harmful consequences. Although withdrawal from benzodiazepines can be problematic, it is rarely life-threatening, whereas withdrawal from prolonged use of barbiturates can have life-threatening complications. Therefore, someone who is thinking about discontinuing a CNS depressant or who is suffering withdrawal after discontinuing use should speak with a physician or seek immediate medical treatment.