ch 9: Drug Misuse and Addiction

what are recreational drugs + most popular (legal + illegal) (4)

• psychoactive substances consumed voluntarily

  • have the potential to be used in a problematic way

• illegal in US → marijuana

• legal drugs: alcohol, tobacco

categories of drugs in Canada (5)

1. prescription drugs: antibiotics, antidepressants, insulin

2. over-the-counter (OTC): acetaminophen, ibuprofen

3. controlled substances: opioids, cocaine, amphetamines

4. natural health products (NHPs): vitamins, herbal remedies

5. cannabis: dried flower, edibles, oils 

what characterizes a drug addiction (3)

• considered to be chronic, relapsing behavioural disorder 

• focus is on compulsive features of drug seeking + use including craving 

• individuals remain addicted for long periods of time → drug-free periods (remission) often followed by relapses 

substance use vs substance-induced disorders (2)

• substance use disorders: cognitive, bhvrl and physiological symptoms indicating that the individual continues using the substance despite significant substance-related problems

• substance-induced disorders: reversible substance-specific syndrome due to recent ingestion of a substance (ie, ↑bp)

substance-related disorders → what do they have in common + what are the 10 classes

• all substances have the ability to activate the neural circuitry that mediates rewards

1. alcohol: beer, wine, spirits

2. caffeine: coffee, tea, energy drinks, pills

3. cannabis: marijuana, hashish THC concentrates

4. hallucinogens: LSD, mescaline

5. inhalants: glue, paint thinners, nitrous oxide 

6. opioids: heroin, morphine, oxycodone, fentanyl

7. sedatives, hypnotics, anxiolytics benzodiazepines, barbiturates

8. stimulants: amphetamine, methamphetamine, cocaine

9. tobacco (nicotine): cigarettes, vaping, chewing tobacco

10. other (unknown) substances 

DSM-5 criteria to diagnose substance use disorder (3)

1. pattern of use must be problematic + must lead to clinically significant impairment or distress

2. no single criterion for determining presence of a substance use disorder

3. severity: mild-severe → depending on how many of the diagnostic criteria are met

____ is the only compulsive behavioural disorder in the DSM-5 → meets several of the criteria for ______ and shows similar _____ and ______ dysfunctions

1. gambling

2. substance abuse disorder

3. neurobiological 

4. cognitive

two types of progression in drug use

1. gateway theory: progress from legal substances like alcohol → marijuana → cocaine/heroin/etc

2. regular pattern → problematic use (addictive) and many people mature out of it → alcohol/illicit drug use decline w age

schedule of controlled substances + factors that need to be considered (4)

• 5 classes → based on degree of potential misuse and medicinal value 

• capture ratio: percent who try a drug and become habitual users

• considering withdrawal, tolerance, reinforcement, dependence, and intoxication

  • heroin, alcohol, nicotine most addictive → caffeine, hallucinogens, cannabis least addictive

about ___% of Canadians (____million people) will meet the criteria for a substance use disorder at some point in their life → many struggle from _____ (AUD) → ___% of males and % of females of the age of ___

1. 21.6%

2. 6 million ppl

3. alcohol use disorder (AUD)

4. 5% of males

5. 2% of females

6. 15

how does addiction correlate w race in Canada? (3)

• significant negative impacts on indigenous communities → solvent abuse 

  • alcohol deaths are twice as high + illegal drug deaths three times as high in indigenous communities vs general population

• also high in African, Caribbean, and Black Canadians 

how does addiction correlate w age in Canada? (4)

• 20-24 year old Canadians are most likely to exceed Canada’s low-risk drinking guidelines 

• age 55 and older tend to use alcohol + other drugs less frequently than younger Canadians

  • alcohol _ prescription drug abuse increases 

  • substance abuse symptoms can mimic other medical/bhvrl conditions

how does addiction correlate w gender in Canada? (4)

• sex differences linked to female reproductive hormones/differences in stress responding

• men are 70% more likely to be dependent on drugs/alcohol

  • men more likely to begin abusing drugs as a part of a pattern of risky bhvr or to enhance social bhvr

  • women: more likely to use drugs to reduce stress, anxiety, loneliness, depression → progress faster from first use to problematic use (telescoping)

how is addiction co-diagnosed with a psychiatric disorder in men vs women (2)

• women: depression, anxiety, phobias

• men: ADHD and antisocial personality disorder

how does the route of administration affect the addictive potential of a substance?

• routes that cause fast onset of drug action have the greatest addiction potential → produce strongest euphoric effects + shortest latency

• shorter latency btw response + reinforcement would lead to stronger + faster drug conditioning

  • IV/inhalation: rapid drug entry + fast onset of drug action → shorter duration

  • oral/transdermal: relatively slow absorption → slow drug availability to the brain

In IV self-administration, how do fixed-ratio and progressive-ratio schedules differ, and what does breakpoint index? (2)

• FR: same number of presses per infusion; yields U-shaped dose–response for reinforcers (low dose = weak effect; mid = peak; high dose = aversion/sedation ↓ responding).

• PR: response requirement escalates each infusion; the breakpoint (last ratio achieved) indexes motivation/reinforcing strength of the drug.

Why do many drugs show a U-shaped self-administration curve under fixed-ratio (FR) schedules? (2)

• Low doses are sub-threshold (not rewarding enough) → low responding; moderate doses maximize reward with tolerable side effects → peak responding;

• high doses produce aversive/sedating/toxic effects or rapid satiation → reduced responding.

In the reinstatement model, what 3 triggers can restore extinguished drug seeking, and what do they represent clinically? (4)

• Drug priming,

• stress, and

• drug-paired cues.

• Clinically map to drug exposure, stressful events, and environmental reminders, respectively—key drivers of relapse in humans.

____ plays a key role in establishing and maintaining drug addiction → withdrawal symptoms (______) motivates users to take the drug again → (_____) 

1. physical dependence 

2. abstinence syndrome 

3. negative reinforcement 

what do the experimental results from heroin studies support in the treatment of opioid-dependence? (2)

• support the use of agonist replacement theory in the treatment of opioid-dependence

  • ie. methadone or buprenorphine

drug-taking behaviour progresses from _____ → ______. this process may be due to _____ system in the brain (_____)

1. impulsive stage

2. compulsive stage 

3. gradual recruitment of an antireward system

4. neuroadapted state

how do genetic factors contribute to the risk for addiction? (3)

• heritability of substance use disorders is in the range of 40-60%

• remaining variability is due to environmental factors → epigenetic and gene-by-environment interactions

  • genetic component is only expressed in ppl w specific life events ie. stressful events 

Name key psychosocial risk factors for developing SUD, especially in adolescence. (10)

1. Younger age;

2. less education;

3. minority status (contextual inequities);

4. unemployment;

5. conduct problems;

6. high stress load & poor coping;

7. family conflict/violence;

8. inadequate parental monitoring;

9. childhood maltreatment;

10. psychiatric comorbidity (anxiety, mood, personality disorders). 🧠

Contrast the self-medication and shared etiology hypotheses for SUD–psychopathology comorbidity. What’s the current evidence? (3)

• Self-medication: people use drugs to relieve symptoms (e.g., anxiety → sedatives).

• Shared etiology: common genetic/environmental vulnerabilities raise risk for both disorders.

• Evidence: not mutually exclusive—both likely operate; varies by person and drug. 🔁

How can social environment raise or lower addiction risk? Give risk and protective examples. (2)

• Risk: social facilitation and drug-using peer groups, subculture norms, loss of conventional roles/responsibilities, family instability.

• Protective: supportive network, stable lifestyle/structure, alternative reinforcers (work, hobbies, sports), and coping-skills training for stress. 🛡

natural recovery from substance misuse + addiction (2)

• transitioning from substance misuse/addiction → non-problematic use → nonuse without assistance

• may be facilitated by transitional life events and/or negative consequences of continuing drug use

what helps the maintenance of abstinence (5)

• avoiding drug-associated cues,

• non-drug sources of reinforcement,

• new social support networks,

• financial stability

• achieving a general structure to the individual’s life

biopsychosocial model of addiction (2)

• includes the full range of pharmacological, biological, and psychological/sociocultural factors that influence addiction risk

• some factors promote the likelihood of substance misuse + addiction → others reduce it

development of addiction has been conceptualized as a repeating cycle of 3 stages:

1. preoccupation with + anticipation of obtaining + using the substance

2. escalating use → drug binges + intoxication

3. withdrawal + associated negative effects 

how do most recreational drugs affect the reward circuit in the brain? (5)

• all recreational drugs activate the mesolimbic DA pathway from the VTA → NAcc

• psycho-stimulants: directly elevate synaptic DA lvls

• opioids/alcohol/nicotine/cannabinoids indirectly ↑ NAc DA

  • opioids: u-opioid disinhibits VTA neurons

  • nicotine excites VTA

  • alcohol/cannabinoids modulate network that increases net DA

_____ important bc early use is dominated by _____ → the drug ___ the probability of ___ bc it feels good/strongly wanted 

1. the mesolimbic DA pathway from the VTA → NAcc

2. positive reinforcement

3. increasing

4. re-use

incentive sensitization theory (4)

• distinction btw liking vs wanting a reward

• drug reward declines due to tolerance

• liking peaks early then declines → wanting increases + stays high

• positive → negative reinforcement

What neural changes drive the preoccupation/anticipation stage of addiction, and how do they bias behavior? (3)

PFC dysregulation (dlPFC/ACC: control↓; vmPFC/OFC: over-valuation of drug cues) ➜ corticostriatal shift from goal-directed (DMS) to habit (DLS) ➜ cue-triggered seeking and poor impulse control → relapse.

In the binge/intoxication stage, distinguish reward (“liking”) from incentive salience (“wanting”) and name the core circuit. (4)

• Liking = hedonic pleasure; wanting = motivational pull of drug/cues.

• Core circuit: mesolimbic DA, VTA → nucleus accumbens (NAc).

• Stimulants ↑ DA directly (DAT effects);

• opioids, nicotine, alcohol, cannabinoids ↑ DA indirectly (e.g., μ disinhibition of VTA).

How do liking and wanting change with repeated use, and what signals stamp in cue–drug learning? (4)

• Liking ↓ (tolerance);

• wanting ↑/persists (incentive sensitization to cues).

• Phasic DA reward-prediction-error signals strengthen cue–drug associations.

  • Opioid & endocannabinoid systems also reinforce.

Which systems mediate the withdrawal/negative affect stage, and how does motivation shift? (2)

• CRF, NE, dynorphin in the extended amygdala → hyperkatifeia (dysphoria, anxiety) and anhedonia.

• Motivation flips from positive (“use to feel good”) to negative reinforcement (“use to stop feeling bad”).

Why can craving reappear long after abstinence? What neural substrates are implicated? (2)

• Long-lasting plasticity in reward (VTA→NAc) and anti-reward (extended amygdala) circuits;

• gene/epigenetic changes and altered synaptic strength sustain vulnerability to cue-induced craving.

Summarize the brain disease vs choice/motivational models of addiction and the testable prediction each makes. (3)

• Brain disease: pathological circuit dysregulation; predicts persistent vulnerability despite intentions.

• Choice/motivational: drug use serves functions (relief, scarce alternatives); predicts changing contingencies (access to non-drug rewards) reduces use. Best view integrates both.

What is contingency management, and why does it work? (2)

• Behavioral treatment delivering immediate, certain non-drug rewards for verified abstinence.

• It reallocates behavior toward alternative reinforcers, countering delay discounting and competing with drug reward.