Addiction - Neurobiology Flashcards
What are the 6 main features in the ICD-10 criteria of dependence?
A strong desire to take the substance / difficulties controlling substance use / physiological withdrawal state / tolerance / neglect of alternative pleasures / persistence despite evidence of harm
What is the CAGE acronym for symptoms of dependence?
Cut-down, annoyed, guilty, eye-opener
What is the neurotransmitter in the reward pathway?
Dopamine
What is the medical term for the reward pathway?
Mesolimbic pathway
What does dopaminergic activity in the mesolimbic pathway do?
It is a motivating signal which incentivises behaviour and is involved in normal pleasurable experiences
As more dopamine is released in the mesolimbic pathway, what happens?
It makes you want to take/do the thing more
What happens if you overstimulate the reward pathway by doing something addictive again and again?
Dopamine receptors will downregulate and a tolerance to reward will develop
Developing a tolerance to a trigger means what?
You will need more of the thing/substance ti achieve the same effect
When you develop tolerance to reward, what effect does this have on normal experiences?
They don’t evoke an adequate reward response
What is positive reinforcement? When does this occur?
Drug taking is driven by reward / In the initial stages of drug taking
What is negative reinforcement?
Drug taking is driven by wanting to avoid feeling rubbish (i.e. it becomes a thirst)
In simple terms, what is the role of the pre-frontal cortex?
To ‘put the brakes’ on the reward pathway and help us make sound decisions
What part of the cortex develops last?
The prefrontal cortex
What is the abnormal significance of the back to front maturation of the frontal lobe cortex?
Areas which mediate executive functioning mature later than limbic (emotional) areas
What is responsible for the increased death rate in adolescents?
They have strong stimulus reward (adult response, developed) but minimal judgement or impulse control (child response, underdeveloped)
Addictive drugs provide a potent signal that disrupts what?
Normal dopamine related learning in the PFC
What is the relationship between addictive behaviour and age?
Once you start doing an addictive behaviour, the pathways get wired into the brain. Therefore, the younger age of onset, the longer the addictive behaviour lasts
Actions surrounding an addiction (for example, opening a cigarette packet) can make a person want to do it more. This is due to the consolidation and expression of drug stimulus learning which takes place in which areas of the brain?
Amygdala, striatum and hippocampus
Learned drug associations can cue what?
Internal states of cravings
The orbitofrontal cortex is the key creator of what? Activity of the OFC increases in addicts when presented with what?
Motivation to act (i.e. whether we do the action or not) / drug cues
What % of the risk of addiction is due to genetic factors?
40-60%
Genetic factors which increase risk of addiction may affect what things?
The way our body metabolically responds to drugs / how rewarding we find drug taking / behavioural traits that predispose us to drug taking
What effect on addiction does having low dopamine receptors have?
It increases the chance of addiction since these people don’t get as much pleasure from normal activities
Acute stress has what effect on drug taking behaviours?
It triggers the release of dopamine in the reward pathway which can motivate drug seeking in dependent individuals
Chronic stress has what effect on dopamine?
It dampens the dopaminergic activity through downregulation of dopamine receptors (i.e. reduces sensitivity to normal rewards)
