Wk 26 - Addiction Flashcards
Define substance abuse
Maladaptive pattern of use of drug, alcohol or other chem agent indicated by continued use despite recurrent social, occupational + physical problem
Define dependence
Psychological, behavioural + cognitive phenomena where substance takes on higher priority
Define addiction
Chronic disease characterised by drug seeking + use that is difficult to control despite harmful consequences
Give examples of Class A drugs
- Crack cocaine
- Ecstasy
- Heroin
- LSD
- Meth
Give examples of Class B drugs
- Amphetamines
- Barbiturates
- Cannabis
- Ket
Give examples of Class C drugs
- Anabolic steroids
- Diazepam
- Khat
Which drugs activate the brain reward system?
- Morphine
- Heroin
- Cocaine
- Alcohol
- Nicotine
Outline the association btw drugs + the brain reward system
- Some drugs have rewarding properties
- Act as reinforcer for self-stimulant of some neural circuits in brain
- Reinforcement inc probability of occurrence of response
What technique is employed by abused substances to facilitate a reward?
Intracranial self-stimulation
Which sites produces ICSS responding?
- Lateral hypothalamus
- Medial forebrain bundle
- Substantia nigra
- Ventral tegmental area
What does SN + VTA stimulation increase the release of?
Dopamine
What does the dopaminergic system consist of?
- Mesolimbic pathway: VTA to nucleus accumbens, amygdala, hippocampus + medial prefrontal cortex
- Nigrostriatal pathway: substantia nigra w/ striatum
- Mesocortical pathway: VTA to cingulate + frontal lobes
- Tuberoinfundibular: arcuate nucleus of mediobasal hypothalamus to infundibular region
What is the Ventral tegmental area?
- Respond to stimuli + cues that indicate presence of reward
- Release DA signals to nucleus accumbens
What is the nucleus accumbens?
- Part of ventral striatum
- Sends projections to basal ganglia + ventral pallidum
What is the Ventral pallidum?
- Located: basal ganglia
- Receives dopaminergic input from ventral tegmental area
What is the orbitofrontal cortex?
Involved: compulsive drug seeking + relapse
What is physical dependence?
- Neurons adapt to repeated drug exposure
- Function normally w/ drug
- Drug tolerance
- Morphine, diamorphine, cocaine + alcohol
- W/drawal reversed by re-admin of drug
What can produce dependence without being a non-addictive drug?
Insulin
What can produce withdrawal symptoms without being a non-addictive drug?
- b3 adrenergic antagonist
- Clonidine
- Tricyclic antidepressants
What is psychological dependence?
- Strong compulsion/desire to experience effect of drug
- Prod pleasures
- Red psychic discomfort
- Nicotine, cannabis + amphetamines
Define withdrawal
Psychological + physiological reactions to abrupt cessation of drug that prod dependence
Define rebound
Emergence or re-emergence of symptoms that were absent/controlled while taking medication, but appear when same med is discontinued or dose red
Define relapse
Recurrence of OG condition from which patient suffered upon discontinuation of effective med treatment
What is pharmacokinetic or metabolic tolerance?
Ability of liver to synthesize more drug metabolising enzymes than normal when exposed to drug
What is pharmacodynamic or functional tolerance?
Change that red reactivity of site to action of drug through:
- NT depletion
- Saturation of receptor site
- Receptor sensitivity alteration
What is behavioural tolerance?
Organisms exposed to drug in 1 context, displays tolerance to drug in that context, but loses tolerance when exposed to drug in another context
