Chapter 6 - How Do Drugs and Hormones Influence the Brain and Behavior

What makes a drug psychoactive?

Alter psychological processes (emotion, thought, perception) by changing neural signaling and crossing the blood-brain barrier.

What are the three basic processes in drug action?

Absorption, blood-brain barrier crossing, and elimination.

What is the main function of the blood-brain barrier?

To protect the CNS by filtering out unwanted or harmful substances. 

What are the 7 points of drug influence at the synapse? 

Synthesis, Storage, Release, Receptor Interaction, Inactivation, Reuptake, Degradation . 

What is agonist?

A drug that mimics or enhances neurotransmitter activity.

What is an antagonist?

A drug that block or decreases neurotransmitter activity

What is tolerance?

A decrease in response to a drug with repeated use.

What is sensitization? 

An increase in response to a drug after repeated use. 

What are the main types of tolerance

Metabolic, Cellular, Conditioned/Learned.

Define Metabolic

Body breaks down drug faster.

Define Cellular

Neurons adapt (fewer receptors).

Define Conditioned/Learned 

Brain learns to counteract effects. 

What happens during withdrawal?

The body produces opposite effects of the drug once use stops (a rebound from learned tolerance.)

What did animal experiments show about tolerance?

Can be learned (practicing under the influence helps the brain adapt to drug effects.

Can tolerance and sensitization occur with the same dug? 

Yes, a drug can cause tolerance to some effects and sensitization to others. 

What neurotransmitter system do most sedative-hypnotics affect?

The GABA system

What are examples of Class I drugs?

Benzodiazepines (Valium), Barbiturates, and Alcohol.

What is the main risk of combining sedative-hypnotics? 

Cross-tolerance 

Define Cross-tolerance

Unpredictable and potentially deadly effects.

What is the main action of antipsychotic drugs? 

They block dopamine (D2) receptors, reducing psychotic symptoms. 

What neurotransmitters are affected by antidepressants?

Mainly amines like serotonin and norepinephrine.

How do SSRIs work?

By blocking serotonin reuptake, increasing its availability in the synapse.

What drug is commonly used as a mood stabilizer for bipolar disorder?

Lithium, though its exact mechanism is unknown.

What neurotransmitter system do opioids act on? 

The endorphin system, especially mu receptors. 

Give examples of opioid drugs.

Morphine, Codeine, Heroin, Oxycodone.

What are psychostimulants, and what do they do?

Drugs like amphetamine, cocaine, and caffeine that increase dopamine activity and alertness.

What are hallucinogens, and what receptors do they act on? 

Drugs like LSD and psilocybin that act on 5HT2A (serotonin) receptors. 

What system does THC act on?

The cannabinoid system (CB1 and CB2 receptors).

How does the DSM define addiction?

A maladaptive pattern of substance use leading to clinically significant impairment or distress.

What are the main addiction theories? 

Physical dependence theory, Genetic determinism, and Wanting and liking theory. 

What does the wanting and liking theory propose?

Drugs first activate liking (pleasure), but over time, wanting (craving) takes over, driving addiction.

How does dopamine relate to addiction?

All addictive drugs increase dopamine release in the nucleus accumbens.

What happens when dopamine neurons are blocked?

Addiction behavior stop but so does motivation for natural rewards (food, sex, etc.)

What role do genetics play in addiction?

influence vulnerability, but environment and learning strongly affect outcomes.

What is the main goal of the brain’s homeostatic drug response? 

To balance the drug’s effects by learning to oppose them. 

What common pattern do most drugs follow?

Use → tolerance → withdrawal → craving → addiction.

Which neurotransmitter system is most tied to motivation and reward? 

The Dopamine system, especially the nucleus accumbens. 

Can all drugs that affect dopamine cause addiction?

No, but most addictive drugs directly or indirectly affect dopamine release.

What key differences separates wanting from liking?

Wanting = motivation to seek the drug, Liking = actual pleasure form using it.