A psychoactive drug is a chemical substance which, when consumed, can affect the brain and nervous system, resulting in an altered mental state. The potent effects of psychoactive drugs have led some to be used as prescription medicines, while others have become some of the most widely prohibited illicit substances in the world. So what are the effects of drugs on the brain? What are the different types of psychoactive drug, and how do these various chemicals affect behaviour, consciousness, mood, perception, and the functioning of the brain?
Depressants slow brain and nervous system functionShow moreShow less
Depressant drugs inhibit signals in the brain and nervous system, reducing neuronal messages and slowing the brain's activity down.
Hypnotics and sedatives are two closely related categories of psychoactive drug, collectively referred to as sedative-hypnotic drugs. These drugs have a range of different mechanisms of action in the brain, but all are used to promote a state of calm, generally by relieving anxiety (in the case of sedatives) or inducing sleep (in the case of hypnotics).
Most sedative-hypnotic drugs work by facilitating the action of inhibitory neurotransmitters, which are the molecules used by the brain and nervous system to dampen the neuronal signals that cause excited feelings and reactions such as stress, fear, and anxiety. Because of their potent effects on the brain's neurochemistry, prolonged use of some sedative-hypnotic drugs can result in memory loss and impaired memory function.
[P1] Sedative-hypnotic drugs work by blocking feelings of excitement, fear and stress from the brain.