Addiction and Reward Flashcards
Addiction
Difficult to truly define, but can be defined as a problematic pattern of usage of an intoxicating substance, according to the DSM-5.
Telescoping
A term that describes the timeframe/how fast someone will go from using a substance for the first time to becoming dependent on that substance, and the impact it has on one’s body.
Studies show women tend to fall into addiction/dependence more quickly than men, even though men are more frequently addicted.
Behavioural/personality variables that increase risk of addiction.
There are three discussed.
1. Behavioural disinhibition (impulsivity, low harm-avoidance, low self restraint, antisociality, aggressiveness)
2. Stress reduction (anxious/stressed/neurotic individuals more likely to fall into addiction)
3. Reward sensitivity (is the individual sensation/reward seeking, extraverted, gregarious)
What causes addiction?
Addiction is caused by altered structure and function of the brain. It alters one’s motivations, leading to increased drug-seeking behaviour.
Addiction has nothing to do with “willpower.”
Stages of Drug Addiction
- Intoxication
- Development of dependence (withdrawal)
- Preoccupation and anticipation
Stages of Addiction
Intoxication
The first stage of addiction. The individual takes the substance, which then affects the nucleus accumbens and dorsal striatum (within the basal ganglia). All addictive drugs involve inducing some form of pleasure. All addictive drugs affect dopamine levels.
Stages of Addiction
Development of Dependence/Withdrawal
The second stage of addiction. When an addicted individual stops taking a drug they are dependent on, they will go into withdrawal, which has negative psychological and sometimes physical effects.
Withdrawal can be very severe for certain people who have been addicted a long time. For example, alcohol withdrawals for people who severely abuse the drug can include seizures, delirium and even death.
Stages of Addiction
Preoccupation and anticipation
The third stage of addiction. Substance-related environmental cues motivate people to seek out a drug and promote incentive salience (physiological motivation/cravings for a drug).
Opponent Process Theory of Drug Addiction
AKA withdrawal theory. The result of the coupling of pleasure while taking the drug and emotional symptoms associated with withdrawal. One needs to take a higher dose of a drug to get a hit (as the brain adjusts to the drug neurotransmitters), or even to get back to a “normal” baseline after becoming addicted.
Example: Caffeine blocks adenosine, if you drink too much coffee, the brain starts to make more adenosine receptors, thus now if you don’t drink coffee you will feel unusually sick and tired as you have adenosine latching onto both your original receptors and new ones produced by your body. You will also need to drink more coffee for the same effects of caffeine if you’ve drank a lot daily consistently. Note this is not a perfect example, as caffeine itself is not considered addictive.
Note: This is a theory, not the whole story. People may have their baseline go back to normal after rehab but still relapse into taking the drug.
In context of addiction & animal experiments
Operant conditioning (specifically positive reinforcement)
Positive reinforcement used to condition an animal: A neutral item is conditioned to have an association with a paired stimulus (a rat gets cocaine after pressing a lever, a rat starts pressing lever more). This also can happen organically with humans and addiction.
Definition of operant conditioning in general: A process of learning where voluntary behaviours are altered by the association of a reward or an aversive stimulus.
Incentive Salience
Motivation for rewards driven by physiological state & learned associations about a specific reward cue.
Eg. Money: Over time we learn money helps us get things we want. Money is the reward cue.
All addictive drugs directly or indirectly increase [answer] transmission.
Dopamine
Dopamine projects from the [answer] to [answer].
Ventral Tegmental Area (VTA) to Nucleus Accumbens (NAcc)
L-DOPA
Prodrug that replaces dopamine in individuals with Parkinson’s disease, reduces symptoms.
Incentive-sensitization theory
This theory distinguishes between wanting a drug (motivation to take a drug) versus liking the drug (gaining pleasure from the drug. Drugs hijack the dopamine system, increasing the motivation to take the drug due to incentive salience (eventually, sight of the drug facilitates motivation).
Model of relapse in animals (Three steps)
Self-administration, extinction, reinstatement
Reward Prediction Error (RPE)
When there is a difference between a predicted reward (predicted by the individual) and the individual’s recieved reward.
Nucleus Accumbens (NAcc)
Recieves many inputs (including dopamine) and guides behaviour (based on valuation). Specifically important to addiction, the NAcc recieves teaching signals that drive our motivations.
What do drugs disrupt in the dorsolateral prefrontal cortex?
Drugs disrupt impulse control, planning and reasoning.
What do drugs disrupt in the dorsal striatum?
The dorsal striatum plays a role in implicit behaviours like habit learning, drugs can hijack the dorsal striatum and along with it one’s habits.
The dorsal striatum is connected to the NAcc.
What role does the amygdala play in drug use?
The amygdala pairs stimuli with reinforcing drug effects.
What role does the orbitofrontal cortex play in drug use?
The orbitofrontal cortex pairs stimuli with reinforcing drug effects.
Psychological and Pharmacological Therapies (Addiction)
Detoxification
Rehabilitation that involves clearing drugs from the body’s systems (involves full abstinence from the drug).
People often relapse from detoxification.
Psychological and Pharmacological Therapies (Addiction)
Drug replacement therapy
Essentially, giving a safer drug to a patient to replace the drug the person is addicted to do. Eg. Giving oral methadone to a heroin addict relieves withdrawal symptoms and cravings.
Psychological and Pharmacological Therapies (Addiction)
Cognitive Behavioural Therapy (CBT)
Therapy to try and rewire thoughts and behaviours that cause an individual to take/crave drugs more.
Psychological and Pharmacological Therapies (Addiction)
Twelve-step programs
A group environment where a sponsor helps individuals through an addiction recovery program. Often combined with spirituality. Often quite effective due to social support.
Psychological and Pharmacological Therapies (Addiction)
Deep brain stimulation of the NAcc
A recent, experimental therapy to treat drug addiction.
These receptors are less present in people who are addicted to drugs long-term.
Dopamine D2 receptors
Jay Hosking’s “Feedforward Mechanism”
Early adverse experiences can be stressors for individuals and can change their development (the most important to note for the feedforward mechanism is changes in development in the NAcc). These adverse experiences can make people more impulsive and less behaviourally flexible, thus they may be more likely to try drugs and become addicted.
Dopamine agonists can cause [answer] disorders.
Impulse control disorders.
Eg. Gambling, hypersexuality, compulsive shopping
Behavioural addictions are often comorbid with [answer] disorders.
Substance use disorders.
