Chapter 5 - Drugs Of Abuse Flashcards
What is the Harrison Narcotics Act of 1915?
One of the first national laws passed to regulate drugs of abuse in the US
What does the Controlled Substance Act establish?
A clarification system for drugs based on their potential medical use and abuse liability
Early definitions of addiction focused on ____ and does not adequately describe ____
Physical dependence (tolerance, withdrawal effects); cocaine, cannabis
Substance Use Disorder
Continued use despite knowledge of significant social, physical, or psychological problems; diagnostic criteria found in DSM 5 and ICD 11
Substance Use Disorder symptoms
Tolerance/withdrawal effects (physical dependence); significant time spent seeking/using drugs (at expensive of other behaviour, work/relationships etc); relapse is likely to occur
Early remission
Symptom free for up to a year
Sustained remission
Symptom free for at least one year
Maintenance therapy
Symptom free using medical treatment; program or medication used to reduce the ability to use
Associative learning
Organism forms associations between two stimuli (classical cond) or a behaviour and a stimulus that follows it (operant cond)
Positive reinforcement (operant cond)
Increased frequency of a behaviour due to a stimulus that followed it (ex drug use to get high is rewarding)
Negative reinforcement (operant cond)
Increase in the frequency of behaviour to remove a stimulus (ex drug use to avoid withdrawal)
Conditioned stimulus (classical cond)
Neutral stimulus associated with drug may become reinforcing (conditioned reinforcer)
Incentive salience (classical cond)
Neutral stimulus commands attention and increases motivation to use a drug
Discriminative stimulus (classical cond)
Stimulus that signal the availability of reinforcement (could be a discrete stimulus or contextual cues in contextual conditioning, ex. A knock on the door means ur plug is here)
Addictive behaviours are ____
Goal-directed
-brain reward pathway determines motivations/drives; drug hijacks reward pathway
Drive theory (theoretical models)
Asserts that repeated drug use leads to a strong, irresistible desire to seek and use the drug; positive reinforcing effects; strength of the drive increases as time passes (like hunger)
Drive strength may also be enhanced by ____ (theoretical models)
Withdrawal effects
-drug seeking reinforced when aversive state is removed (negative reinforcement)
Opponent-process theory (theoretical models)
Starts with the idea that for every action, there is a re-action; when a drug produces an initial effect, it automatically triggers an action/process in the body to counteract the drugs effect; body “needs” drug to balance opposing process
Allostasis (opponent process theory)
Maintenance of a balance around a new set point
How does allostasis relate to the opponent process theory?
As long as drug is present, the drug effects and the opponent processes “balance” out at the altered set point however when the drug wears off the body is no longer in balance as the opposing process is still active
-person seeks out drug to maintain allostérie balance
The opponent process theory emphasizes ____
Negative reinforcement
-drug seeking/taking is used to prevent withdrawal effects (opponent processes)
Incentive salience model (theoretical models)
Argues that drug addiction occurs after there is a shift from how much a drug is “liked” to how much a drug is “wanted”
Relapse (incentive salience model)
Return to drug use; may result from re-encountering a stimulus with high incentive salience
-encouraging a stimulus with high incentive salience may command attention and re-engage drug seeking behaviour
Disease model of drug addiction
Drug addiction is characterized as a medical disease; drug is seen as cause of disease; one may have a predisposition for drug addiction; treatment goal is to manage the disease
Drugs of abuse affect (directly or indirectly) the brain’s ____
Reward pathway; specifically the mesolimbic dopamine pathway from the VTA to the nucleus accumbens
What does the mesolimbic dopamine pathway do in drug abuse?
Pathway is activated by naturally rewarding stimuli (food, sex, etc) however drugs of abuse powerfully activate and “hijack” this pathway, making drugs more desired
What is the Reward Circuitry?
Olds and Milner (1954) designed an operant chamber equipped with a level; electrons placed in the medial forebrain bundle of rats; rats could then press the level to stimulate their own brain
-rats pressed up to 5000 times per hour; did not eat/drink/etc
The amount of ____ released is proportional to the ____ (reward circuitry)
dopamine; expectation of the reward
When DA is released into nucleus accumbens it…. (reward circuitry)
Inhibits GABA neurons, leading to disinhibition of GABA and increased DA release
Amygdala’s role in the reward circuit
Forms associations between stimuli and reward pathway activation
-connected to thalamus and frontal cortex
-when reward effects are expected but don’t occur the amygdala may initiate a stress response via cxn to hypothalamus
-activation of amygdala inhibits DA neurons in the VTA (anti reward process!)
Orbitofrontal cortex’s role in reward circuitry
Increased incentive value of conditioned stimuli leading to cravings (inputs from amygdala and thalamus)
Hippocampus’s role in reward circuitry
Forms associations between environmental contexts and reward pathway activation; important for conditioned place preference effects; mediates dopamine release in environments in which drugs of abuse were experienced
Dorsolateral prefrontal cortex’s role in reward circuitry
important for executive control— planning actions/decision making
-important for making choices (ex delay immediate gratification for bigger reward)
-compromised with chronic drug use; more impulsive, less decisions, etc
Basal ganglia’s role in reward circuitry
Important for automatic, procedural memories; becomes increasingly engaged with drugs of abuse; readily for repetitive, compulsive behaviours associated with drug use (ex reaching for a cig and lighting it while driving)
Intoxication (addiction stage)
Acute drug effects that produce a maladaptive and impaired state
What is involved in the intoxication stage?
The reward system
Withdrawal (addiction stage)
Repeated drug use results in physical and/or psychological withdrawal effects
What parts of the brain are involved with withdrawal?
Amygdala, hypothalamus, ANS
Preoccupation/anticipation (addiction stage)
Behaviour orients from seeking natural reinforcers to seeking drug reinforcers
What parts of the brain are involved with preoccupation/anticipation?
Prefrontal cortex, amygdala, thalamus, hippocampus
Therapy/treatment must begin with ____ which involves ____
Detoxification; easing the withdrawal symptoms as drug administration is stopped
-two key approaches: medication + the prevention
Drug replacement therapies
Involve exchanging the addictive drug to a more socially acceptable alternative
Cognitive-behavioural therapy
Designed to aid the drug user in engaging strategies to reduce to urges to use the drug
Twelve-step anonymous programs
Involve anonymous testimony and guidance through 12 steps of recovery
Food addiction
Compulsive eating shares many similarities with drug addiction; underlying reward circuitry involved in drug addiction is also involved in food addiction
