Addiction Flashcards
what are the causes of addiction?
- Genetic
- Environmental – psychological stressors, ACEs
- Age – adolescents
- Comorbid – ADHD, PTSD
how is stress related to addiction?
acute stress triggers dopamine release, chronic stress causes downregulation of D receptors
which neuro pathway is the reward pathway?
mesolimbic pathway
what neurotransmitter is largely involved in addiction?
Dopamine
where is dopamine produced from?
VTA midbrain
what areas of the brain are involved in the mesolimbic pathway?
Amygdala
Nucleus Accumbens
Prefrontal cortex
Hippocampus
what is the role of dopamine?
DA is released when we experience pleasure and
removed from synaptic space into neuron by DA receptors triggering response and neuron activation
DA molecules are then removed from receptors and reabsorbed back via DA transporter
what are the dopamine levels in addiciton?
Initially elevated
As addiction continues brain limits amount - tolerance
what is the role of noradrenaline in addiction?
o NA and A released to put bodies in motion to complete addictive act
o Upregulation of ATP to allow for the increased production of noradrenaline
o Explains jitters in withdrawal and tolerance
what is the mechanism of tolerance development?
o Due to repeated dopamine release, dopamine receptors are down regulated
o Threshold for rewards during abstinence is increased.
what are the drivers of addiction?
Initially - reward (positive reinforcement)
Later - need (negative reinforcement)
what are the two ways that drugs can affect the brain pathway?
o Artificially mimic one of the naturally occurring NTs
o Alter availability of a NT
what are the common types of addiction?
Drugs, alcohol, gaming, extreme sports, social media, sexual
what are the different types of mimicking drugs?
Opiates
Nicotine
Alcohol
what is the mechanism of opiates?
similar structure to endorphin so binds to endorphin receptors - effect more powerful than natural substance
what is the mechanism of nicotine?
mimics ACh which triggers release of dopamine, glutamate and GABA (prevents inhibited response to dopamine)
what is the mechanism of alcohol?
binds to receptors for ACh and 5-HT causing sedative effects
Slower communication between neurons
Brain compensates by increasing production of NT
what are the examples of altering drugs?
Cocaine
Meth
Amphetamines
what is the mechanism of cocaine?
interrupts the reabsorption of DA and NA
High concentrations of DA and NA overstimulates the neurons and the person feels pleasure and energy
what is the effect of smoking meth?
causes excessive release of DA. Eventually the brain starts to produce an enzyme which will break down DA and reduce its ability to produce more
what are the CAGE features of addiction?
cut-down, annoyed, guilty, eye-opener
what is the ICD-10 criteria for addiciton?
o A strong desire to take the substance o Difficulties in controlling substance use o A physiological withdrawal state o Tolerance o Neglect of alternative pleasures o Persistence despite evidence of harm
what affect does alcohol have on the CNS?
depressant
what is the initial effect of alcohol in the brain?
depression of inhibitory neurons (feel relaxed + disinhibited)
what is the later effect of alcohol in the brain?
down-regulation of inhibitory neuronal gamma-aminobutyric acid receptors, up-regulation of excitatory glutamate receptors, and increased central norepinephrine activity
what parts of the brain are affected by alcohol?
Hypothalamus and Pituitary Glands, Medulla, nucleus accumbens, cerebral cortex, prefrontal cortex, cerebellum
what is the effect of alcohol on the hypothalamus and pituitary glands?
Increases sexual arousal, decreases ability to engage in sexual activity
what is the effect of alcohol on the medulla?
Increases sleepiness, Slows breathing, Lowers body temp
what is the effect of alcohol on the nucleus accumbens?
Pleasant or rewarding feelings
what is the effect of alcohol on the cerebral cortex?
difficulty thinking, difficult to speak clearly
what is the effect of alcohol on the prefrontal cortex?
More relaxed, Less self-conscious
what is the effect of alcohol on the cerebellum?
Affects coordination, Difficulty walking and driving
what neurotransmitter does alcohol largely affect?
GABA - enhances effect
what are the different factors that can contribute to alcohol misuse?
Genetic Psychological Occupational Cultural Availability
what are the psychological factors that contribute to alcohol misuse?
children who are impulsive, aggressive and hyperactive, also anxiety
what occupations factors are implicated in alcohol misuse?
doctor, entertainer, wine merchant, bar staff, armed forces, publican, journalists
what are the cardiovascular consequences of alcohol misuse?
o moderate intake protective?
o high intake – increases BP – increases risk of IHD, CVA Stroke, arrhythmias
what are the hepatic consequences of alcohol misuse?
hypoglycaemia, lactic acidosis – leads to fatty liver, cirrhosis, oesophageal varices, hepatitis (reduced clotting factors, reduced albumin, asterixis, jaundice
what are the GI consequences of alcohol misuse?
gastritis, pancreatitis (nausea, vomiting, abdo pain, haematemesis), poor teeth
what are the blood consequences of alcohol misuse?
anaemia (macrocytic, megaloblastic)
what are the consequences of sexual function in alcohol misuse?
o short term increases
o long term damages leydig cells – causing decreased testosterone = loss of libido, infertility, loss of male body hair
what are the neuropsychiatric consequences of alcohol abuse?
o vitamin B peripheral neuropathy and dementia o withdrawal = seizures o sleep – decreases REM, poorer quality o impaired memory o depression/anxiety o Subdural hematoma
what are the dermatology consequences of alcohol abuse?
increased superficial cutaneous vasculature, urticarial reactions, porphyria cutanea tarda, flushing, cutaneous stigmata of cirrhosis, psoriasis, pruritus, seborrhoeic dermatitis, and rosacea
what is the ICD-10 criteria for alcohol abuse?
A pattern of psychoactive substance use that is causing damage to health. The damage may be physical or mental
what is the ICD-10 criteria for alcohol dependence syndrome?
o Strong desire or sense of compulsion to take drug
o Difficulty in controlling use of substance in terms of onset, termination or level of use
o Physiological withdrawal state
o Evidence of tolerance
o Progressive neglect of other pleasures/interests because of use or effects of substance
o Persistence with use despite clear evidence of harmful consequences
what are the 1st line investigations in alcohol abuse?
diagnostic interview alcohol level (breath + blood) Withdrawal assessment
what are the different tools used for diagnostic interviewing in alcohol abuse?
AUDIT
CAGE
TACE
Also - TWEAK, MAST, PAT, FAST
what AUDIT score indicates low risk drinking?
0-7
what AUDIT score indicates hazardous drinking?
8-14