Addiction Flashcards
Define addiction.
Relapsing-remitting disorder comprising behaviours that are performed in a compulsive manner in spite of the potential for self-harm
What is dependence?
Characterised by a state of withdrawal when the substance of abuse (e.g. drugs or gambling) is removed
What are the 3 types of behaviours associated with dependence?
- Drug-seeking/craving: anticipation of obtaining/taking a drug prior to use
- Binging/intoxication: taking substance, highs + issues of tolerance/dependence
- Withdrawal: -ve effects of removal of drug/not taking drug
What are the 2 types of dependence?
- Psychological: need to keep performing compulsive behaviours characterised by emotional distress on stopping
- Physical: need for functional effect of drug on body characterised by physical withdrawal symptoms
What is tolerance?
Requirement for increasing amount of drug/behaviour to elicit same level of +ve reinforcement (‘high’) as that experience during previous exposures to the substance/behaviour
What are the 3 different types of tolerance?
- Acute: repeated exposure to drug in short period of time e.g. cocaine high decreases in 1 night
- Chronic: constant exposure over prolonged period of time e.g. opioids
- Learned: frequent exposure to substance becomes integrated into normal behavioural routines e.g. alcohol
What is withdrawal?
Prolonged and painful process as an effect of removing substance/object of dependence but NOT the same as ‘crash’ when +ve effects wearing off and you get rebound dip in mood/behaviour - termed detoxification or detox when performed actively
Why does a crash occur?
Occurs before plasma drug levels drop so it not directly related to decreasing drug activity, it is due to changes in regional neuronal activation once the high occurring in striatum, thalamus, nucleus accumbens and cortical regions begins to subside, other areas (e.g. striatum + extended amygdala) involved in -ve aspects become more dominant
What are some common withdrawal symptoms?
Psychological: confusion, anhedonia, headache and fatigue
Physical: tachycardia, tachypnoea + tremor
What is Post-Acute Withdrawal Syndrome (PAWS)?
Symptoms experienced after prolonged period of withdrawal occurring a couple of months following initial withdrawal predominantly causing psychological effects rather than physical in acute stage e.g. insomnia, mood swings, anxiety + anhedonia
What brain areas are involved in dependency and their associated behaviours?
mPFC + orbitofrontal cortex + hippocampus: preoccupation, craving, conditioned cues + anticipation
Amygdala, BNST + ventral striatum (inc. n. accumbens): -ve emotions, dysphoria, malaise + withdrawal
Thalamus, dorsal striatum + GP: reward, binge, intoxication, euphoria + habit
What is the cycle of addiction/dependence?
- Binge occurs following a period of salience
- Anticipation then occurs followed by executive function
- Executive function causes neuroadaptation such as circuit, synaptic
+ molecular changes - Stress occurs followed by withdrawal after
What 3 key factors influence whether a person is more or less likely to become dependent?
- Genetics (polygenic inheritance)
- Environment e.g. in utero or personal choice
- Route of administration (injection > inhalation > snorting > ingestion)
What is nicotine?
A substance that acts both centrally in brain and peripherally in the autonomic ganglia via nicotinic cholinergic receptors acting as a stimulant and relaxant - PARASYMPATHOMIMETIC
What does nicotine do?
Stimulant effect: release of ACh, NA and A via ANS
+ve mood and addictive qualities: endorphins, DA + 5-HT - cognitive enhancement + increase in fine tuning of movement thought to provide +ve reinforcement underpinning addiction