Module 1: Individual (micro) Models Flashcards
(38 cards)
What is the proper definition for addiction?
Addiction is defined as a chronic, relapsing brain disorder characterised by compulsive drug seeking and use, despite its harmful consequences
What does it mean by when addiction is a “brain disorder”?
It explains that addiction causes changes to the structure and functioning of the brain, and it is maintained by these changes
What does it mean by when addiction is “chronic”?
It suggests that addiction is a long-term illness with periods of remission and relapse. Although it is possible to get better, it is unlikely that a person will completely give up the substance and will go back to it
What does it mean by when addiction is “characterised by compulsive drug seeking and use”?
That there is a loss of control over substance use and the illness has taken over their will (regardless whether they want to do it or not)
What is addictive?
A substance that acts as a reward to our brains; it is the thing that helps develop an addiction
What are the 4 types of addictive?
- Stimulants
- Depressants
- Hallucinogens
- Mixed
What is a stimulant? List the possible effects and examples
A stimulant is a addictive that brings you up. For instance, it would increase your attention and energy, BP/HR. If it goes up too high beyond its optimal, one could develop heart problems, paranoia or have seizures. An example of a stimulant could be caffeine, nicotine or cocaine.
What is a depressant? List the possible effects and examples
A depressant is a addictive that brings us down (giving us low energy/slowing us down). Some of the effects of depressants include: sedation, reduction in anxiety, lowered BP, and slowed breathing. However, excessive use of depressants can be fatal, causing confusion, learning and memory impairment. Some examples could include: Alcohol and opioids.
What is a hallucinogen? List the possible effects
Hallucinogens is a addictive that causes the individual to see hallucinations. Some effects include perceptual change - sounds can be louder than usual, colours may seem brighter than usual.
Where does the word addiction originate from?
The word addiction comes from the Latin term “addictus,” which means “bound to” or “enslaved by.” In ancient Rome, the term was used to describe someone who was legally bound to a creditor or slave owner.
What is the DSM?
A categorical system for the classification, diagnosis and treatment of a mental disorder
How does the DSM work?
It provides diagnostic criteria for a wide range of mental disorders. The diagnostic criteria will have categories and within those categories include a description of the specific symptoms/behaviours that are characteristic of that disorder
What is a reward? What kinds of rewards are there?
In addiction, a reward is a pleasurable experience/feeling that a person experiences as a result of substance use and it acts as a stimuli to provide positive reinforcement for that behaviour.
There are natural/primary rewards which are essential for human survival and include food, water, and sex. Other rewards could also include learning, approach behaviours and feelings of positive emotion
How do drugs affect the brain reward system?
Drugs can affect the brain’s reward system by hijacking the natural processes of pleasure, which is regulated by neurotransmitters such as dopamine. When drugs are taken, they can increase the amount of dopamine that is released in the brain’s reward system → strong sense of pleasure
What are the 2 types of animal models used to study drug reward? Explain these models:
- Self-administration: This model involves training animals to self-administer a drug by pressing a lever or engaging in some other behavior. Animals will learn to work to obtain the drug, demonstrating the rewarding effects of the drug
- Conditioned Place Preference (CPP): In this model, animals are trained to associate the effects of the drug with a particular environment or context.
What was the main method used to study brain reward? Explain the procedure
Intracranial electrical self-stimulation (ICSS) was used to find out which area of the brain was involved in the reward system.
It involves implanting metal electrodes → mesolimbic system, specifically in the NAc
What are the ways that the reward pathway be can blocked?
- By surgically cutting the pathway from the VTA
- Chemically by administrating dopamine antagnoist
Explain how the mesolimbic system works in the reward pathway
The mesolimbic system is a brain pathway that is involved in reward, motivation and addiction. It consists of dopaminergic neurons that originates from the VTA of the midbrain (where the cell bodies are located) and connects to the limbic system, including NAc, amygdala and prefrontal cortex.
The mesolimbic system works as follows:
- Trigger a rewarding stimuli: When we experience something pleasurable or feel a positive emotion, it triggers the release of dopamine in the VTA
- Dopamine release: The dopaminergic neurons in the VTA release dopamine —> synapses of the NAc, amygdala and prefrontal CX.
- Reinforcement of Behaviour: The activation of postsynaptic neurons —> feelings of pleasure and reinforcement of the behaviour that triggered the dopamine release
What is dopamine?
A NT that is involved with many brain functions such as motivation, movement, reward and reinforcement learning.
What is the VTA?
The VTA is located in the midbrain and is involved in the brain’s reward system (reward, motivation and reinforcement learning). It is comprised of GABA, glutamate neurons and dopaminergic neurons that extend to the NAc and prefrontal cortex.
What is the NAc?
The NAc is the brain’s ‘pleasure centre’. It is located in the basal ganglia and receives input from neurons of the VTA, hippocampus, amygdala and prefrontal cortex.
What is an angonist?
Drugs that bind to a receptor and activates it, mimicking the effects of natural compounds in the body
What is an partial angonist?
Same as angonist but produces a weaker response
What is an antagnoist?
A type of drug/compound that blocks/inhibits the activity of a receptor meaning that it prevents other molecules (NT) from binding and activating the receptor (ie: will not produce a response)
