Substance use & Addiction Flashcards
what is the typical course of alcohol/drug use, harmful use and addiction?
recreational use, no difficulties
want/need becomes increasingly regular use (harmful use)
need - spiralling dependence (addiction)
what is harmful use of drugs/alcohol?
actual damage caused to mental/physical health in the absence of diagnosis of dependence syndrome
what is dependence?
strong desire or compulsion to take drug
difficulties in controlling taking drug - onset, termination, levels of use
physiological withdrawal state when stopped/reduced
evidence of tolerance
progressive neglect of alternative interests
persisting with substance use despite evidence of consequences
what drug causes the most harm in the UK?
alcohol in both harm to users and harm to others
what is addiction vs dependence?
addiction is compulsive drug use despite harmful consequences
dependence is a physical and biological adaption to a substance
what factors affect addiction?
social, environmental factors
specific drug factors
personal factors (genetic, personality etc)
how does alcohol acutely affect brain chemistry?
blocks NMDA receptor (blocks excitatory)
therefore impaired memory
boosts GABA-A receptor (boosts inhibitory)
therefore anxiolysis, sedation
how does alcohol chronically affect brain chemistry?
upregulation of excitatory system to adapt to NMDA receptor being blocked chronically
reduced function in inhibitory system as GABA-A switches subunits to be less sensitive to alcohol
how do you treat alcohol withdrawal?
benzodiazepines to boost GABA function
how does alcohol withdrawal affect brain chemistry?
NMDA receptor upregulated, increase of Ca2+ leading to hyperexcitability (seizures) cell death
how is addiction reinforced?
reward deficiency - positive reinforcement
overcoming adverse state e.g anxiety/withdrawal - negative reinforcement
impulsivity and compulsivity
what is the reward pathway in the brain?
ventral striatum dopamine system
how do cocaine and amphetamines impact dopamine rewards?
block reuptake - prolonged effect of dopamine
-amp also enhances dopamine release
How does other drugs like alcohol etc affect the dopa pathway
increase ventral tegmental pathway firing
levels of what can predict extent of reinforcing/rewarding brain responses?
levels of D2 receptors in the brain
higher D2 leads to less pleasurable responses
what change in brain chemistry makes some addicts more likely to relapse?
blunted response to anticipation of reward in ventral striatum
what regions of the brain are involved in bingeing/intoxication?
dorsal striatum
what regions of the brain are inolved in withdrawal?
brainstem, hypothalamus