Transcript CHEMICAL MESSENGERS

MODELS OF ADDICTION:
A SUMMARY
Moral / Temperance Model *
Addiction as Sin or Crime
Personal Irresponsibility
Disease Model *
Genetic and Biological Factors
12-Step Framework; Abstinence
Education as Treatment
Behavioral and CognitiveBehavioral Models *
Conditioning and Reinforcement
Social Learning and Modeling
Drug Expectancies and other
Cognitive Factors / RP
Family Models
Family Disease
Family Systems
Behavioral Marital/Family Tx
Medical / Disease
Models of Addiction
MODELS OF ADDICTION
Assumptions of Disease Model
addiction seen as a “primary” disease process
alcoholics qualitatively different from non
alcoholics: can’t drink in moderation
central symptom of addiction is loss of control
(e.g., one drink, one drunk)
addiction is chronic and progressive; no cure,
can only be arrested with total abstinence
(e.g. progression models - Johnson…learning &
seeking the mood swing; harmful dependence;
drinking to feel normal)
Genome Wide Association Studies: Website
BIOLOGY OF ADDICTION
• Introduction
• Why study addiction from a biological perspective?
All Multicell Organisms Require Cellto-Cell Communications
Mammals Require a Variety of
Sophisticated Systems for Chemical
Communications
CHEMICAL MESSENGERS
 Chemical Messengers
 Hormones—Released from glands and
affect other cells, including other glands
 Neurotransmitters—More discrete and
targeted than hormones
 Receptors—Cell structures that receive
the chemical message
Electro-Chemical Signaling in the Nervous System
Information Movement in the Nervous System
Release of Neurotransmitter Molecules
7 Neurotransmitters Related to Drug Effects
The 3 Monoamines
1. __________ - common and pervasive chemical important in
regulation of motor movements, emotional and cognitive
processes, and reinforcement
- schizophrenia (increased dopamine activity)
- Parkinson’s Disease (decreased activity)
• Different drugs affect dopamine levels in different ways:
 stimulants like cocaine and amphetamines
increase dopamine activity
7 Neurotransmitters Related to Drug Effects
2. _____________ - important in regulation of sleep and mood
monoamine theory of depression supported by:
drugs that reduced Monoamines produce depression
drugs effective in treating depression act on serotonin
or norepinephrine
3. _________________ - important in the regulation of hunger,
alertness and arousal; implicated in depression / mood
regulation
7 Neurotransmitters Related to Drug Effects
4. _______________(ACh) - important in the functions of muscular
activity, regulation of thirst and memory
(e.g. Alzheimer’s Disease is related to loss of cholinergic
function in brain)
5. ______________ - thought to modulate pain relief and to be
associated with naturally occurring pleasures or “highs”
6. _______ - (__________-___________________ acid)
referred to as an inhibitory transmitter because when it binds to
receptor sites it stops the neuron from firing.
What drugs act on this system? ______________________
7. _______________ – throughout brain; excitatory
BIOLOGY OF ADDICTION
• neuron is like a rechargeable battery, can fire again after
either:
enzymes break down transmitter substance so it cant
occupy receptor site anymore or
reuptake: substance taken back into terminal button
•
agonists and antagonists
______________ is any chemical (naturally occurring
in brain or introduced) that fits a receptor lock and
activates it;
in general, ___________ increase the activity of the
transmitter systems they operate on
(ex. morphine is an agonist for the endorphins )
Some
Mechanisms of
Drug Action
- drug can decrease or
increase synthesis of
neurotransmitters
- neurotransmitter
transport interference
- neurotransmitter
reuptake is blocked
(pictured)
- receptor activation;
drug mimics
neurotransmitter
- receptor blocking
BIOLOGY OF ADDICTION
___________________ - don’t activate receptor sites and
neurons to fire but still occupy site, preventing other
chemicals from sitting there
ex.
_______________________________________
___________________________________________
___________________________________________
NEURAL BASIS OF REWARD & ADDICTION
• studies of stimulation of rat brains:
• There is possibly a final common pathway for positive
stimulation and reward; these pathways are dopamine-rich;
• most drugs produce changes in this system, but “broccoli”
(food) does not produce dramatic changes…
Why not?
NEURAL BASIS OF REWARD & ADDICTION
 “body” and brain memories…
amygdala activated prior to drug ingestion in cocaine
users compared to controls
 “addicted brain” is qualitatively different from non-drug users
even after drug use is discontinued
e.g. _____________________________
A Few Definitions
Psychopharmacology - study of the effects of drugs on behavior
Pharmacology -
the study of drugs and their effects;
• Pharmacokinetics __________________________________________________
__________________________________________________
• Pharmacodynamics __________________________________________________
__________________________________________________
Brainstorm
What factors relate to the way drugs affect
us?
Brainstorm
Drugs need to get into the body before
exerting an effect...how many different
ways can drugs enter the body and brain?
The 4 major routes of drug administration

Oral

Injection
subcutaneous intramuscular intravenous -
The 4 major routes of drug administration

Inhalation - absorbed through lungs…

Absorption
intranasal - mucous membranes of nose, sinus
sublingual - under the tongue; absorbed through
mouth’s mucous membranes
transdermal - through the skin; examples?
rectal - suppositories
Pharmacokinetics
 Absorption: rate and extent to which drug leaves its site
of administration;
bioavailability: portion of drug that reaches its site of action
 Distribution: where the blood flows most is where most
of the drug goes (where? _________)
 Elimination: liver enzymes play biggest part in expelling
drugs; kidneys as well
 where excreted? _______________________
 drug half-life: ___________________________
Pharmacodynamics
 dose-effect curve
effective doses - % of people who experience
effect of drug at given doses
 ED - 50 ; 50% of people taking specific dose
will be experiencing the effect
lethal doses - effect of interest is death! Defined
as % of animal subjects who die
LD - 50
•
Major Implications: _____________________________
____________________________________________
Behavioral Pharmacology and Tolerance
Behavioral Pharmacology - specialty area within pharmacology
that concentrates on drug use as learned behavior
General Definition of tolerance - reduced response to a drug after
repeatedly taking it
Types of Tolerance:

Dispositional tolerance - increase in the ______
_____________________ a drug after repeated use

Functional (cellular) tolerance- _____ becomes
_________ sensitive to drug
• acute tolerance: occurs within single dose or first few
doses of drug
(e.g., Alcohol
cocaine)
• vs. protracted:occurs after regular,chronic use
Behavioral Pharmacology and Tolerance
• Behavioral tolerance - person adjusts or compensates for
their drug-induced behavior
EX. We compensate for intoxicated behavior in diff ways
_______
• Issue of cross-tolerance EX. ________________________
• tolerance to some effects of drug but not others
• tolerance syndrome doesn’t develop to some drugs
•
reverse tolerance - becoming more sensitive with repeated
use (examples ?)