The Brain Drugs

Psychoactive drugs are chemicals that cross the blood-brain barrier and alter brain chemistry and functioning; these drugs lead to changes in perception, cognition, volition, mood, or behavior.

The blood-brain barrier is the barrier between circulating blood and the extracellular fluid of the brain.

The blood-brain barrier consists of tightly-bound cells lining blood vessels in and around the brain.

Drugs must cross the blood-brain barrier in order to have a psychoactive effect.

Re-uptake is the reabsorption of some neurotransmitters by special receptors in the presynaptic membrane.

An agonist is a chemical that binds to a receptor and activates its function; it behaves like the receptor’s endogenous substrate.

An antagonist is a chemical which binds to a receptor but has no action on it; instead, it prevents other substrates from binding, effectively turning off the receptor’s function.

An SSRI, selective serotonin reuptake inhibitor, is any drug that inhibits reuptake of serotonin, with little to no effect on other neurotransmitters.

This SSRI method is the most common mechanisms among contemporary antidepressants.

The following are six common SSRIs:

1. Fluoxetine (Prozac)

2. Citalopram (Celexa)

3. Escitalopram (Lexapro)

4. Fluvoxamine (Luvox)

5. Paroxetine (Paxil)

6. Sertraline (Zoloft)

An antipsychotic is a type of drug used to manage psychotic symptoms such as delusions and hallucinations.

There are two broad categories of antipsychotics: typical, or first-generation, and atypical, or second-generation, which gained popularity in the 1970s. Both types have been shown to have a high incidence of undesirable side effects.

1. Chlorpromazine (Thorazine)

2. Haloperidol (Haldol)

1. Clozapine (Clozaril)

2. Olanzapine (Zyprexa)

3. Risperidone (Risperdal)

4. Quetiapine (Seroquel)

A benzodiazepine is a class of drugs based on a particular structure that has sedative and anxiety-reducing effects.

1. Alprazolam (Xanax)

2. Diazepam (Valium)

3. Lorazepam (Ativan)

4. Clonazepam (Klonopin)

An anxiolytic is any drug that produces anxiety-reducing effects.

Anxiolytics include most benzodiazepines and antidepressants.

A neuroleptic is a category of drug used to manage psychotic symptoms, such as delusions and hallucinations, and is synonymous with antipsychotic.

Neuroleptics have a high incidence of undesirable side effects.

Clozapine was the first atypical (second generation) antipsychotic drug to be discovered in the 1950s. It is more effective than older (first generation) antipsychotics, but there still remain many adverse side effects.

Adverse side effects of Clozapine include:

1. Agranulocytosis (lowered white blood cell count)

2. Excessive weight gain

3. An increased likelihood of developing diabetes

An MAOI, monoamine oxidase inhibitor, is a class of antidepressant that functions by inhibiting monoamine oxidase (MAO), an enzyme which breaks down serotonin, dopamine, and norepinephrine.

A decrease of MAOs leads to an increase in these neurotransmitters and, in effect, an improved mood.

MAOIs can have very dangerous side effects, and are rarely prescribed today.

A tricyclic antidepressant is the oldest class of antidepressant; it functions by blocking the re-uptake of both serotonin and norepinephrine.

Tricyclic antidepressants are quite effective, but because they can be lethal in high doses, they are rarely prescribed today.

A mood stabilizer is any drug used to treat the mood shifts that characterize certain mood disorders, such as the mania and depression shifts of bipolar disorder.

Well-known mood stabilizers include lithium and valproic acid.

A stimulant is any drug that induces alertness or wakefulness, and improves mental or physical functioning.

Stimulants are often used to treat ADD and ADHD, as well as narcolepsy and other sleep disorders.

1. Caffeine

2. Nicotine

3. Amfetamine

4. Methylphenidate

1. Cocaine

2. Crystal meth

3. MDMA (“Ecstasy”)

A depressant is any drug that reduces the activity of a certain part of the brain or body.

The umbrella group of depressant includes the following, among others:

1. Alcohol

2. Antipsychotics

3. Antihistamines

4. Barbiturates

5. Benzodiazepines

6. Opioids

An opiate is any narcotic substance derived from the opium poppy plant; opiates are considered to be the most effective drugs for relieving pain.

1. Morphine

2. Heroin

3. Codeine

Although heroin and morphine are both opiates and are nearly identical, the effects of heroin are much stronger than morphine.

The structure of heroin contains extra acetyl groups, allowing it to more easily cross the blood-brain barrier.

A dissociative is any drug that produces feelings of detachment from oneself and one's environment.

Dissociatives are often classified under the category of hallucinogens.

1. Ketamine

2. PCP (Phencyclidine)

3. DXM (Dextromethorphan)

A psychedelic drug is a kind of drug that creates unfamiliar and unusual states of consciousness through alterations in cognition and perception, including hallucinations.

Six examples of psychedelic drugs are:

1. LSD

2. Psilocybin

3. Mescaline

4. Ketamine

5. PCP

6. MDMA

1. Tolerance

2. Withdrawal

Tolerance is a symptom of physiological dependence to a drug in which higher doses of the drug are needed to produce the same effects as in the past.

Withdrawal is a symptom of physiological dependence of a drug in which ceasing use of the drug causes adverse effects and seriously disrupts the user's functioning.

Alcohol is a universally common depressant, ingested via alcoholic beverages, that increases the effects of the neurotransmitter GABA in the brain.

The specific alcohol in alcoholic beverages is ethanol.

Nicotine is one of the most addictive drugs on Earth and can act as either a stimulant or a sedative, producing feelings of both alertness and calmness.

Nicotine functions by binding to acetylcholine receptors in the brain.

Nicotine is the active chemical in tobacco.

Caffeine is the psychoactive ingredient in coffee and tea; it acts as a highly addictive stimulant.

Caffeine functions by antagonizing adenosine receptors and increasing neural activity.

Marijuana is any preparation of the plant genus Cannabis that causes effects including elevated mood,
hallucinations, abstract or philosophical thinking, and sometimes paranoia.

Marijuana is one of the most commonly used illicit substances in the world.

LSD, lysergic acid diethylamide, is an extremely potent hallucinogen; it functions by binding to many types of receptors, including those for serotonin, dopamine, and epinephrine.

Psilocybin is the psychoactive chemical present in several species of mushrooms; it produces hallucinations by working as a serotonin agonist.

MDMA, or "ecstasy", is considered a "party drug", and produces the subjective effects of increased empathy, elevated mood, and increased openness.

MDMA functions by increasing the release of serotonin, dopamine, and norepinephrine by neurons, and causing oxytocin release.

Cocaine is a highly addictive and harmful stimulant extracted from the coca plant; it produces effects such as euphoria, increased energy, and talkativeness.

Cocaine functions by blocking the re-uptake of dopamine and affecting both serotonin and norepinephrine.

Ketamine is a dissociative anesthetic; it produces effects such as dissociations and hallucinations.

Ketamine functions by antagonizing specific receptors that ultimately block the action of glutamate.

PCP, phencyclidine, is a dissociative drug; it causes dissociations and hallucinations, similar to ketamine, but the effects last longer.

PCP functions by antagonizing specific receptors, in effect blocking the action of glutamate.