WEEK 4: MECHANISM OF ADDICTION Flashcards
What is addiction?
*Drug addiction is a chronic disease that affects a person’s brain and behavior and leads to an inability to control the use of a legal or illegal drug or medicine.
*Addiction is also known as substance dependence
*A cluster of behavioral, cognitive, and physiological phenomena that develop after repeated substance use
*maladaptive pattern of substance use leading to clinically significant impairment or distress
*Addiction is a disease characterized by behavioral issues
What is drug dependence?
Drug dependence is a state of needing one or more drugs to function or to avoid discomfort.
refers to when a person requires one or more drugs in order to function.
chronic, progressive disease characterized by significant impairment that is directly associated with persistent and excessive use of a psychoactive substance.
dependence is a physical or psychological reliance on something.
dependence refers to the physical need for the drug to operate normally
Outline the criteria for dependence.
*Tolerance : Drug tolerance is a condition where a drug becomes less effective after repeated use
*Withdrawal: Drug withdrawal refers to the process your body goes through when you try to stop taking drugs or are unable to take drugs for whatever reason.
*Use in larger amounts or for longer periods than intended
*Persistent desire or unsuccessful efforts to cut down on alcohol use
*Time is spent obtaining alcohol or recovering from effects
*Social, occupational and recreational pursuits are given up or reduced because of alcohol use
*Use is continued despite knowledge of alcohol-related harm (physical or psychological
Why do people take drugs?
*Curiosity because others are doing it or
*Peer pressure
*To feel good - Drugs can make you feel good for a short while
*Experimenting…and then again….and again
*To do better - Confidence to face difficult situations / better performance.
*To feel better- Helping to forget your problems
*Loneliness, unhappiness
*If you use alcohol or a drug more and more, you will become dependent on it
*If you hang out with people who use drugs, you probably will too
State the addictive drugs
1.Stimulants
*Amphetamines: speed, meth
*Cocaine
*Caffeine
2.Nicotine : Tobacco
3.Alcohol
4.Cannabinoids: marijuana, hashish
5.Opioids: Heroin, Opium
6.Prescription Medications
*Opioid Pain-Killers: Morphine, Codeine, Fentanyl, Pethidine, methadone, oxycodone, hydromorphone,
*CNS Depressants: Barbituates, Benzodiazepines, Hypnotics, Methaqualone
*Stimulants : Amphetamines, Methylphenidate
*Other prescription drugs: Dextromethorphan (cough mixture)
State the factors that determine addiction
1.ENVIRONMENTAL/ SOCIAL
2.BIOLOGICAL FACTORS
3.DRUG FACTORS
1.Environmental (social) factors – as above
Chaotic home and abuse
Parent’s use and attitudes
Peer influences
Community attitudes
Poor school achievement
2.Biological Factors
Genetics – account for 40-60 % of vulnerability to addiction
Gender - males
Mental illness –higher risk of substance abuse and addiction
Level of development – adolescents at higher risk
3.Drug Factors
Availability
Route of administration
Cost
Early use
Effect of the drug
Outline risk factors(social) for drug abuse and addiction -Childhood
HOME AND FAMILY
a lack of attachment and nurturing by parents or caregivers;
ineffective parenting
a caregiver who abuses drugs
drug availability
Poverty
Community attitudes or tolerance
PEER AND SCHOOL
poor classroom behavior or social skills.
academic failure
association with drug-abusing peers
drug availability
Attitudes and tolerance
Describe the psychological theories of drug addiction.
1.Psych-analytic
2.conditioning theory
3.Personality traits
1.Psycho-analytic
*Traumatic early experiences
*Need for oral gratification.
*Death wish explaining the self-destructive process.
2.Conditioning Theory
*Withdrawal avoidance and reward
*Modelling
3.Personality traits
*Some psychologists believe that there is an “addictive personality”
*This has not been scientifically proven
*Appears however that certain personality traits make people vulnerable to substance abuse:
-Sensation seeking personality trait
-Impulsive trait
-Anti-social personality
Describe to the relation between brain and addiction
Addiction is a condition that involves craving, loss of control, and adverse consequences1. It changes the brain by affecting its reward system, which releases chemicals like dopamine and glutamate in response to pleasurable experiences23. Addiction also impacts other brain areas, such as the brainstem, the cerebral cortex, and the limbic system, that regulate impulses, learning, and motivation45. Addiction can be caused by various substances, such as stimulants, nicotine, opioids, alcohol, and sedatives, that enter the brain and bloodstream and trigger the reward system4. Breaking an addiction is tough, but possible1.
What happens in addiction is that, through completely natural processes involved in all learning, the brain prunes nerve pathways of attention and motivation to preferentially notice, focus on, desire, and seek the substance. What starts out as a choice becomes, in a sense, a prison.
What is reward system?
The reward system refers to a group of structures that are activated whenever we experience something rewarding like using an addictive drug. When exposed to a rewarding stimulus, the brain responds by increasing release of the neurotransmitter dopamine. Thus, structures that are considered part of the reward system are found along the major dopamine pathways in the brain. The pathway most often associated with reward is the mesolimbic dopamine pathway, which starts in an area of the brainstem called the ventral tegmental area, or VTA. The VTA is one of the principal dopamine-producing areas in the brain and the mesolimbic dopamine pathway connects it with the nucleus accumbens, a nucleus found in a part of the brain that is strongly associated with motivation and reward called the ventral striatum.
When we use an addictive drug or experience something rewarding, dopamine neurons in the VTA are activated. These neurons project to the nucleus accumbens via the mesolimbic dopamine pathway, and their activation causes dopamine levels in the nucleus accumbens to rise.
Another major dopamine pathway, the mesocortical pathway, also originates in the VTA but travels to the cerebral cortex, specifically to the frontal lobes. It is also activated during rewarding experiences and is considered part of the reward system.
Because dopamine is released whenever we use an addictive drug, researchers initially thought dopamine must be the neurotransmitter that causes pleasure. More recent research, however, suggests that dopamine activity doesn’t correlate exactly with pleasure. For example, dopamine neurons are activated before a reward is actually received and thus before the pleasure is experienced. For this (and other) reasons, it is now thought dopamine has roles other than causing pleasure, such as assigning importance to environmental stimuli associated with rewards and increasing reward-seeking.
Whatever the precise role of dopamine in reward is, the mesolimbic dopamine pathway is consistently activated during rewarding experiences, leading it to be considered the main structure of the reward system. Regardless, the actual network of brain structures involved in mediating reward is much larger and more complex than just this dopamine pathway, involving many other brain regions and neurotransmitters
Link the limbic system to addiction
The limbic system;
*contains the brain’s reward circuit
regulate our ability to feel pleasure
*pleasure motivates us to repeat behaviors such as eating
*also activated by drugs of abuse
the limbic system is responsible for our perception of other emotions, both positive and negative, which explains the mood-altering properties of many drugs
Describe the biology of addiction
*Most drugs of abuse directly or indirectly target the brain’s reward system by flooding the circuit with dopamine
*Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and feelings of pleasure.
*The overstimulation of this system, which rewards our natural behaviours, produces the euphoric effects sought by people who abuse drugs and teaches them to repeat the behaviour.
*the brain adjusts to the overwhelming surges in dopamine (and other neurotransmitters) by producing less dopamine or by reducing the number of receptors that can receive signals
*As a result, dopamine’s impact on the reward circuit of a drug abuser’s brain can become abnormally low, and the ability to experience any pleasure is reduced
*This is why the abuser eventually feels flat, lifeless, and depressed, and is unable to enjoy things that previously brought them pleasure
*Now, they need to take drugs just to try and bring their dopamine function back up to normal
*And, they must take larger amounts of the drug than they first did to create the dopamine high—an effect known as tolerance
Why the abuser eventually feels flat, lifeless, and depressed, and is unable to enjoy things that previously brought them pleasure?
What is the term used to refer to loss of pleasure?
Because of development of TOLERANCE
*the brain adjusts to the overwhelming surges in dopamine (and other neurotransmitters) by producing less dopamine or by reducing the number of receptors that can receive signals
*As a result, dopamine’s impact on the reward circuit of a drug abuser’s brain can become abnormally low, and the ability to experience any pleasure is reduced
ANHEDONIA
State other effects of drugs on the brain
*impairment in cognitive function (alters glutamate levels in the brain)
*Results in craving to environmental cues by triggering adaptations in non-conscious memory
*Chronic exposure to drugs of abuse disrupts the way critical brain structures interact to control and inhibit behaviours related to drug abuse
*Addiction is now considered by some a brain disease because drugs change the brain—they change its structure and how it works
*The brain changes can be long lasting, and can lead to the harmful behaviours seen in people who abuse drugs
Why does introduction of drugs in childhood and adolescence has worse consequences?
The brain is still developing in childhood and adolescence which is why introducing drugs has worse consequences.
