Discussion-Addiction Flashcards
What is drug use
Drug taking in any form
Does not imply problematic behavior
Drug use is not the same as drug abuse
What is a drug
A substance that is used primarily to bring about a change in some existing process or state, be it psychological, physiological or biochemical
Food effects studied by nutritionists
Drug effects are studied by pharmacologists
How are drugs classified
They are usually by behavioral or pharmacological effect Stimulants Depressants Analgesics Hallucinogens Psychotherapeutics
What are the top 5 drugs being abused
Marijuana Prescription pain relievers Prescription tranquilizers Cocaine Prescription stimulants
How is drug abuse and addiction defined
Clinically -DSM-IV: -Substance Abuse -Substance Dependence -DSM-V: -Substance abuse disorders Pharmacologically -Compensatory mechanisms/adaptations
Changes in the DSM-V
Combined substance dependence and abuse: -Substance Use Disorders Defined by level of severity: -Mild (2-3 Criteria Met) -Moderate (4-5 Criteria Met) -Severe (6+ Criteria Met) Distinct Terms for Specific Substances: -Ex: Cannabis Use Disorder -Excludes Caffeine Drug Craving added to criteria Behavioral Addictions: -Gambling Disorder -Number of criteria that must be met is different Exclusion of legal problems
Moral Model About Addiction being a brain disease
Addicts are people who CHOOSE drugs over work, family, and society due to their bad morals or weaknesses
Medical Model About Addiction being a brain disease
Addicts suffer from a chronic brain disease, which can lead to difficulty in stopping use
Studying drug use with animal models
Study causal effects Ethical Limitations Access to Additional Tools There are many animal models, that isolate different behaviors associated with addiction -Drug-taking -Motivation for drug -Resistance to punishment -Craving and Relapse
Common Animal Models
Conditioned Place Preference (CPP)
Conditioned Place Aversion (CPA)
Self-Administration
Conditioned Place Preference/Aversion
Saline injection paired with one side
Drug injection paired on other side
On test day (drug free), where does animal spend time?
-
Drug Self Administration
Animal performs an action (operant behavior) to receive a reward (drug infusion/sucrose pellet)
Can vary requirements for reward
-Fixed Ratio (FR) Schedules
-Drug-Taking
–Rate of Response
Ex: FR1-one response equals one reward
FR5-five responses equals one reward
-Progressive-Ratio (PR) Schedules (Drug-Seeking)
Motivation:
-Break Point
–Each subsequent reward requires an exponentially higher level of responses
-Can add punishment component
-Resistance to Punishment
–Foot Shock
–Each response results in a reward but is also paired with foot shock
Is Self Administration Addiction
Not entirely due to unnatural circumstances
Usually single housed with minimal enrichment
No social interactions, toys, or stimulation
Self-administration sessions are the most interesting part of their day
Nothing in chambers to interact with except for the levers/nose ports
The animal can sleep or administer drugs
Drug-Taking
Self-administration of drug of their own volition
Drug-Seeking
Compulsively seeking drugs even when they are not available
Resistance to Punishment
Responding even when drugs are paired with painful stimuli
Increased drug motivation
Exerting more effort to obtain drug over time
Relapse
Taste of drug or seeing cues can trigger relapse
Role of Dopamine in Addiction
DA signaling from Ventral Tegmental Area (VTA) to Nucleus Accumbens (NAc) implicated in the rewarding effects of many rewards
Addictive drugs increase dopamine transmission from VTA to NAc
How doe Dopamine promote drug-taking
Dopamine release is believed to be associated with pleasure. Many drugs enhance dopamine release and are therefore believed to be pleasurable.
Positive Reinforcement
During the negative state of withdrawal, dopamine release via drug taking relieves withdrawal symptoms
Negative Reinforcement
Allostatic Model-Withdrawal Avoidance
Cessation of Drug use—Low DA levels—Low mood—Desire to boost mood/dopamine with drugs—Drug use and relapse
Support
-Withdrawal associated with low dopamine levels
-Many drugs increase mood and release dopamine
-Drug cues elicit negative mood, which can be alleviated by drug taking
Issues
-Relapse probability does not decrease after withdrawal has passed
-Drug cues enhances DA levels. They do not decrease them
Anhedonia Theory
Support for it
Dopamine mediates the hedonic impact of rewards. Addicts just have unusually low levels of dopamine and use drug to increase them and the hedonic impact of rewards
Support:
-Addictive drugs produce euphoria
-Dopamine release enhanced by nearly all drugs of abuse
Issues:
-Dopamine is released before drug administration
-Dopamine is released in aversive situations
-Dopamine lesions/antagonists do not reliably block drug-induced euphoria
-Dopamine agonists do not reliably enhance hedonic reactions
Affective reactions to various stimuli that can be objectively measured
Liking reactions to sweet taste
Disgust reactions to bitter taste
Appetitive eating behavior
Defensive fearful behavior
Does dopamine cause pleasure
Liking reactions are not abolished after dopamine lesions or altered with amphetamine administration
Incentive Sensitization
Drugs produce pleasure, but it isn’t driving addiction
-Drugs and drug cues releasing dopamine cause excessive “wanting” (craving, desire)
-Drug cues are powerful
-Drugs and drug cues gain incentive salience
-Wanted can be separated from liking
Drugs cause excessive wanting by:
-Promoting sensitization of dopamine system
-Cue-drug associations can be learned
-Gain incentive salience themselves
-This causes uncontrollable wanting of drugs not necessarily liking
This explains why relapsing is so common and can happen decades later
-Modifications to dopamine system result in long lasting changes. It is sensitized. May not like drug, but want it.
Psychomotor Sensitization
Direct test of capacity of drugs to produce incrementally increasing behavioral changes. Indirectly models the addictive process.
Associated with motivational sensitization
Incentive Sensitization
Support and issues
Support:
-Craving happens before withdrawal
-Craving induced by drug use itself
-Even drugs with small withdrawal are highly addictive
>Amphetamines, cocaine
-Nicotine is highly addictive, not very euphoric
-Dopamine depletion does not affect liking
Issues:
-Chronic drug use is sometimes associated with low dopamine levels
-Not clear why sensitization causes excessive wanting of drugs and not all things
Why are sex differences important
Historically the therapies that have been developed from male data
There are sex differences:
-Drug taking
-Drug effects
-Motivation
Important to develop therapies based on differences
