Addictive Behaviours Midterm Chapters 1-4

Why is addiction considered a neurobiological disorder rather than simply a moral failure?

Addiction causes measurable changes in brain structure and function that alter motivation, reward processing, decision-making, memory, emotion, and self-control

What is the Central Nervous System (CNS)?

The CNS consists of the brain and spinal cord and serves as the body's primary control and communication system

What are the major functions of the Central Nervous System?

The CNS processes information, regulates emotions, drives motivation, controls behaviour, and coordinates movement

What is a neuron?

a specialized nerve cell whose primary function is communicating with other neurons through electrical and chemical signals

How do neurons communicate with one another?

Through electrical impulses (action potentials) and chemical messengers (neurotransmitters).

What are the four major structural components of a neuron?

Cell body (soma), dendrites, axon, and axon terminals.

What is the function of the cell body (soma)?

It contains the nucleus and cellular machinery responsible for metabolism, maintenance, and overall control of the neuron

What is the primary function of dendrites?

receives incoming signals from other neurons and carry that information toward the cell body.

What is the primary function of the axon?

The axon carries electrical signals away from the cell body toward the axon terminals

What is the function of axon terminals?

They release neurotransmitters into the synapse, allowing communication with the next neuron

What is an action potential?

is an electrochemical impulse that travels down the axon after the neuron reaches its activation threshold.

What is the All-or-None Rule of action potentials?

A neuron either fires completely or does not fire at all—there is no partial firing.

What is a synapse?

is the tiny gap between two neurons where neurotransmitters are released to transmit signals

Why is the synapse especially important in psychopharmacology?

Most psychoactive drugs produce their effects by altering communication at the synapse

What are the three major functions of neurons?

Sensory processing, motor control, and cognition/emotion.

What does sensory processing involve?

Receiving information from the environment, such as vision, hearing, and touch.

What does motor control involve?

Controlling voluntary and involuntary body movements

Why are cognition and emotion especially important in addiction?

Addiction disrupts thinking, planning, decision-making, emotional regulation, and other higher cognitive functions

What are glial cells (glia)?

are supporting brain cells that outnumber neurons and actively regulate brain functioning and neurotransmission

Why was the traditional view of glial cells incorrect?

Scientists once believed glia only supported neurons, but research shows they actively influence neurotransmission, brain function, and addiction

Approximately how do glial cells compare in number to neurons?

Glial cells outnumber neurons and make up most of the cells in the brain.

How do glial cells influence neurotransmission?

They regulate neurotransmitter activity and help remove neurotransmitters from the synapse through reuptake mechanisms

What are astrocytes?

are a major type of glial cell responsible for regulating neurotransmitters and maintaining the brain's chemical environment

What is neurotransmitter reuptake?

is the process of removing neurotransmitters from the synapse after they have transmitted a signal

Why is neurotransmitter reuptake important?

It ends the signal between neurons and prevents excessive stimulation of the nervous system

Which drugs commonly target neurotransmitter reuptake systems?

Cocaine and many antidepressants

Which neurotransmitter do astrocytes help regulate that is especially important in addiction?

Glutamate

Why is glutamate regulation important in substance use disorders?

Dysregulation of glutamate is linked to addiction-related brain changes and substance use disorders

What are neurotransmitters?

are chemical messengers that allow neurons to communicate with one another

What is the sequence of neurotransmission?

Action potential reaches the axon terminal → neurotransmitters are released into the synapse → neurotransmitters cross the synaptic cleft → bind to receptors on the next neuron → the signal is transmitted

What is dopamine's primary role?

Dopamine is involved in reward, motivation, and reinforcement and is the neurotransmitter most strongly associated with addiction

What are serotonin's primary functions?

Mood regulation, sleep, and appetite

What are norepinephrine's primary functions?

Arousal, alertness, and the body's stress response.

What is GABA? (gamma-aminobutyric acid)

is the brain's primary inhibitory neurotransmitter

What is the function of GABA?

It reduces neural activity and helps calm brain function

Which substances primarily act on GABA systems?

Alcohol and benzodiazepines

Which neurotransmitter is most closely linked to reinforcement and addiction?

Dopamine

Which neurotransmitter is primarily inhibitory?

GABA

Which neurotransmitter is primarily associated with mood regulation?

Serotonin

Which neurotransmitter is primarily associated with alertness and stress responses?

Norepinephrine

Which major brain systems are most involved in substance use and addiction?

The brainstem, basal ganglia, amygdala, cerebral cortex, hippocampus, and dopamine pathways.

What are the primary functions of the brainstem?

It controls essential life-sustaining functions such as breathing, heart rate, blood pressure, and sleep-wake cycles

Why are opioids especially dangerous to the brainstem?

They suppress the brainstem's respiratory centers, which can cause respiratory depression and death during an overdose.

What is respiratory depression?

A dangerous slowing or stopping of breathing, which is the leading cause of death in opioid overdoses.

What is the locus coeruleus?

A brainstem structure that becomes hyperactive during opioid withdrawal

What symptoms occur when the locus coeruleus becomes hyperactive during opioid withdrawal?

Sweating, vomiting, increased heart rate, and severe physical discomfort

What is the basal ganglia?

A group of subcortical brain structures located between the brainstem and cortex that play a major role in addiction and reward

What is the nucleus accumbens?

A structure within the basal ganglia often called the brain's reward center because it plays a central role in reward and reinforcement.

Where does the nucleus accumbens receive most of its dopamine input from?

The ventral tegmental area (VTA)

What is the mesolimbic dopamine pathway?

A dopamine pathway connecting the ventral tegmental area (VTA) to the nucleus accumbens that is primarily responsible for reward and reinforcement.

What natural behaviours does the mesolimbic dopamine pathway normally reinforce?

Eating, social bonding, and reproduction

How do addictive drugs hijack the brain's reward system?

They produce dopamine surges much larger than natural rewards, making drug use seem far more rewarding

Why do natural rewards become less appealing during addiction?

Drugs repeatedly overstimulate the reward system, reducing the motivational value of everyday rewards

What is the primary function of the amygdala?

Processing fear, anxiety, and emotional responses

Why is the amygdala important in addiction?

It contributes to stress, anxiety, and dysphoria experienced during withdrawal

What is the cerebral cortex responsible for?

Higher-order functions such as reasoning, language, planning, and self-control

What is the function of the anterior cingulate cortex (ACC)?

It monitors conflict, regulates behaviour, and detects situations where desires conflict with long-term goals

How does impaired anterior cingulate cortex function contribute to addiction?

It reduces a person's ability to resist impulses and stop drug-seeking behaviour

What are the major functions of the dorsolateral prefrontal cortex (DLPFC)?

Working memory, planning, cognitive flexibility, and future-oriented thinking

How does chronic substance use affect the dorsolateral prefrontal cortex?

It reduces grey matter density and weakens neural connections, leading to poor planning and reduced self-control

What is the primary role of the orbitofrontal cortex (OFC)?

Evaluating rewards and assigning value to different outcomes

How does addiction affect the orbitofrontal cortex?

Drugs become overvalued, causing individuals to continue using despite serious negative consequences

What is the function of the insular cortex (insula)?

It creates awareness of internal bodily sensations and plays a major role in craving

What evidence suggests the insula is central to craving?

Some people who suffer damage to the insula after a stroke report that their urge to smoke disappears completely.

What is the primary role of the hippocampus?

Forming memories and learning associations between experiences and contexts

How does the hippocampus contribute to relapse?

It stores associations between drug use and specific people, places, smells, and routines, allowing environmental cues to trigger cravings months or years later

What are the four major dopamine pathways in the brain?

Mesolimbic, mesocortical, nigrostriatal, and tuberoinfundibular pathways

Which dopamine pathway is most important in addiction?

The mesolimbic pathway

What is the function of the mesolimbic dopamine pathway?

Reward, reinforcement, and motivation

What brain regions does the mesolimbic pathway connect?

The ventral tegmental area (VTA) and the nucleus accumbens

What is the function of the mesocortical dopamine pathway?

Executive functioning, judgment, planning, and self-control

How does dysfunction of the mesocortical pathway contribute to addiction?

It impairs judgment and self-control, leading to poor decision-making

What is the function of the nigrostriatal dopamine pathway?

Controlling movement

Which neurological disorder is primarily associated with degeneration of the nigrostriatal pathway?

Parkinson's disease

What is the primary function of the tuberoinfundibular dopamine pathway?

Hormonal regulation, particularly controlling prolactin secretion

Does the tuberoinfundibular pathway play a significant role in addiction?

No. It has minimal direct involvement in addiction.

Why is calling dopamine the "pleasure chemical" inaccurate?

Dopamine primarily signals salience and motivation—it tells the brain what is important to pursue rather than directly producing pleasure

What does it mean that dopamine signals "salience"?

It tells the brain, "This matters," increasing motivation to obtain a reward

How do addictive drugs manipulate dopamine signalling?

They convince the brain that obtaining the drug is more important than natural rewards or survival-related behaviours

What is psychopharmacology?

The study of how drugs affect the mind by acting on the body and nervous system.

Why is the route of drug administration important?

It influences how quickly a drug reaches the brain, how it is distributed throughout the body, the intensity of its effects, and its addiction potential

Why does faster drug delivery generally increase addiction risk?

Faster delivery produces quicker dopamine surges, creating stronger reinforcement and increasing the likelihood of addiction

Rank the major routes of administration from highest to lowest addiction potential.

Intravenous (IV) → Smoking/Inhalation → Intranasal → Oral.

What is enteral administration?

Drug administration through the gastrointestinal (GI) tract, typically by swallowing or placing medication under the tongue

What is the most common form of enteral administration?

Oral administration

What are the advantages of oral administration?

It is convenient, safe, and easy to use

What are the disadvantages of oral administration?

It has the slowest onset of action and is affected by first-pass metabolism

What is sublingual administration?

Placing a drug under the tongue where it is absorbed directly into the bloodstream

What are the advantages of sublingual administration?

Faster absorption and avoidance of first-pass metabolism

What medication commonly uses the sublingual route?

Buprenorphine

What is parenteral administration?

Delivering drugs by injection rather than through the digestive system.

What is subcutaneous administration?

Injecting a drug just beneath the skin, producing relatively slow absorption.

What is intramuscular administration?

Injecting medication into muscle tissue, producing moderate absorption because muscles have a rich blood supply

What is intravenous (IV) administration?

Injecting a drug directly into a vein, producing the fastest delivery to the brain

Why does intravenous administration have the highest addiction potential?

It delivers the drug directly into the bloodstream, producing rapid brain exposure and intense dopamine release.

What are the major health risks associated with intravenous drug use?

Infection, HIV, hepatitis C, and other blood-borne diseases

What is transdermal administration?

Drug delivery through the skin over an extended period.

What is a common example of transdermal drug administration?

Nicotine patches

What is intranasal administration?

Delivering drugs through the nasal passages where they are rapidly absorbed through blood-rich tissues

Name two drugs commonly administered intranasally.

Cocaine and naloxone (Narcan)