Unit 1.3.C: The Neuron and Neural Firing - Psychoactive Drugs

Psychoactive drugs

Drugs that change your thoughts, mood, or behavior by affecting the brain.

Agonists

Drugs that mimic a neurotransmitter and increase its effect.
(They “boost” the signal.)

Antagonists

Drugs that block a neurotransmitter from working.
(They “stop” or reduce the signal.)

Reuptake inhibitors

Drugs that block reuptake, so neurotransmitters stay in the synapse longer and have a stronger effect.
(Example: SSRIs for serotonin.)

Stimulants

Drugs that speed up the brain and body — more energy, alertness, and mood elevation.

Caffeine

A mild stimulant that increases alertness by blocking adenosine (a sleep-related chemical).

Cocaine

A powerful stimulant that blocks dopamine reuptake, causing intense euphoria and energy.

Depressants

Drugs that slow down the brain and body — produce relaxation and reduced anxiety.

Alcohol

A depressant that slows neural processing and reduces self-control and judgment.

Hallucinogens

Drugs that distort perception, causing users to see or hear things that aren’t really there.

Marijuana

A hallucinogen that alters perception, mood, and memory.

Opioids

Drugs that relieve pain and create a sense of euphoria by acting like endorphins.

Heroin

A highly addictive opioid that creates intense pleasure and pain relief.

Tolerance

When your body gets used to a drug, so you need more of it to feel the same effect.

Addiction

A condition where someone cannot stop using a drug even when it harms them.

Withdrawal

The unpleasant symptoms that happen when a drug user stops taking the drug.
(Examples: shaking, anxiety, nausea, pain.)