Welcome – to the place where Chemistry and Neuroscience meet up! This blog is devoted to the science behind drugs varying from controlled substances to prescription drugs to even over-the-counter drugs. However, there will be one underlying similarity between all of the drugs we will be talking about. We specifically want to focus on ‘How do certain drugs affect the brain?’ To understand such a broad, yet complicated topic, we first need to go into the basics.
So what are the basics of Psychopharmacology? In this primary post, we wish to touch upon some preliminary, and necessary, definitions.
Drugs that affect the brain are called psychoactive drugs. Psychoactive drugs are defined as any chemical substance that crosses the blood-brain barrier and alter cognition, memory, mood, perception, consciousness, or behavior.
Ignoring the complicated structures in the brain, this image shows the blood-brain barrier. In order for any substance to enter the brain’s extracellular fluid, it must enter through the blood-brain barrier.
As you may already know, there are many psychoactive drugs; however, they can all be categorized into a few main types: Stimulants,Depressants, Narcotics, Hallucinogens and depending on the source – Anxiolytics and Euphoriants.
Stimulants, as the name implies, temporarily improve mental and/or physical functions. You can almost think of it in terms of thermodynamics. Stimulants increase Gibbs Free Energy (G), or the maximum ability to do work. And as any high school student would know, or at least those that stay up past midnight, caffeine is a perfect example of a stimulant.
Depressants, once again as the name implies, depress activity within the brain. They do so by increasing levels of the neurotransmitter GABA. This does not necessarily mean that a person has less energy (although that is certainly true in some cases) but rather that neural activity has slowed. In kinetics, depressants would be the inhibitor, causing the reaction to take more time.
Narcotics are drugs that have sleep-inducing effects and/or are used as painkillers. Narcotics may also induce a sense of euphoria. Narcotics are sometimes put as a subcategory of depressants because of the sleep-inducing qualities of narcotics that will slow the mental processes of a user.
Hallucinogens are the type of psychoactive drugs that alter perception, thought, emotion and consciousness. A well known drug from the 1960’s is Lysergic acid diethylamide, better known as LSD, and is a hallucinogen.
Euphoriants are the type of drugs that cause a state of euphoria (e.g. MDMA, or ecstasy). However, since so many drugs can induce a sense of euphoria, this category is often left out. Similarly to some euphoriants, anxiolytics induce a sense of relaxation and inhibit anxiety. Very often these drugs are used for medical purposes to treat anxiety disorders.
Each of these drugs affects our brain in one way or another. As we will see in the next blog, all of these drugs interfere with neurons and neural receptors. Some drugs will inhibit normal behavior whiles others will amplify normal behavior.
But good bye until next time!
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