Substance-Related Disorders Flashcards
Define addiction
a condition that results when a person ingests a substance (e.g. alcohol, cocaine, nicotine) or engages in an activity (e.g., gambling, sex, shopping) that can be pleasurable but the continuation of which becomes compulsive and interferes with ordinary responsibilities and concerns, such as work, relationships, or health
What areas of the brain involved in the dopamine pathways involved with reward, pleasure, euphoria, motor function, and decision making?
- Prefrontal cortex
- Hippocampus
- Nucleus accumbens
- Ventral tegmental area***
- Raphe
What are the areas of the brain involved in the serotonin pathways involved with mood, memory, sleep, cognition?
- Prefrontal cortex
- Hippocampus
- Nucleus accumbens
- Ventral tegmental area***
- Raphe
What activities and substances may activate the reward pathways in the brain?
- food
- water
- sex
- activities (such as sky diving, roller coasters, etc.)
- exercise
What are the 4 neurotransmitters acting on the reward pathway
- dopamine
- serotonin
- cannabinoids
- opioid peptides (endorphins, enkephalins)
Dopamine
- receptors
- function
- receptors: D1, D2
- function: pleasure, euphoria, mood, motor function
Serotonin
- receptors
- function
- receptors: 5HT3
- function: mood, impulsivity, anxiety, sleep, cognition
Cannabinoids
- receptors
- function
- receptors: CB1, CB2
- function: pain, appetite, memory
Opioid peptides (endorphins, enkephalins)
- receptors
- function
- receptors: Kappa, Mu, Delta
- function: pain
Name the final chemical activator in the reward pathways.
Dopamine!
Neurotransmitter’s anatomical sites
-dopamine
- ventral tegmental area
- nucleus accumbens
Neurotransmitter’s anatomical sites
-opioid peptides
- nucleus accumbens
- amygdala
- ventral tegmental area
Neurotransmitter’s anatomical sites
-GABA
- amygdala
- bed nucleus of stria terminalis
Neurotransmitter’s anatomical sites
-glutamate
-nucleus accumbens
MOA of cocaine to facilitate dopamine activity in the CNS
- via reuptake inhibition of dopamine
- dopamine release is promoted via the protein responsible for the reuptake of dopamine (dopamine transporter; DAT)
*an example of direct drug action
Action of alcohol in reward pathway
inhibit GABAergic neurons that project to dopaminergic neurons in the VTA
Action of heroin in reward pathway
binds to opioid receptors that inhibit GABAergic neurons that project to dopaminergic neurons in the VTA
Action of cocaine in reward pathway
blocks the function of DAT (by binding to the DAT and slowing transport)
Action of nicotine in reward pathway
activates cholinergic neurons that project to dopaminergic neurons of the VTA
What are the the 4 changes observed in the CNS after abrupt withdrawal of a substance that has produced tolerance?
- disturbance of the autonomic nervous system
- activation of the thalamus
- release of corticotrophin releasing factor (CRF)
- activation of the locus coeruleus (LC)
What system mediates affective and somatic symptoms of drug withdrawal?
Corticotrophin Releasing Factor (CRF) system
Name the physiological changes observed during drug withdrawal.
the patient feels dysphoric, irritable, depressed, and angry
What are the symptom(s) mediated by dopamine when intoxicated by a drug of abuse?
euphoria
What are the symptom(s) mediated by opioid peptides when intoxicated by a drug of abuse?
- analgesia
- relaxation
What are the symptom(s) mediated by serotonin when intoxicated by a drug of abuse?
elevated mood
What are the symptom(s) mediated by GABA when intoxicated by a drug of abuse?
- decreased anxiety
- less panic
- relaxation
What are the symptom(s) of withdrawal mediated by dopamine?
dysphoria
What are the symptom(s) of withdrawal mediated by serotonin?
dysphoria
What are the symptom(s) of withdrawal mediated by opioid peptides?
increased pain
What are the symptom(s) of withdrawal mediated by GABA?
- anxiety
- panic attacks
What are the symptom(s) of withdrawal mediated by NPY?
anti-stress
What are the symptom(s) of withdrawal mediated by dynorphin?
dysphoria
What are the symptom(s) of withdrawal mediated by CRF?
stress
What are the symptom(s) of withdrawal mediated by norepinephrine?
stress
What are the symptom(s) of withdrawal mediated by glutamate?
hyperexcitability
Describe the 5 steps of addiction development.
- the use of the drug of abuse is increased to maintain euphoria or to avoid dysphoria or withdrawal
- the # of receptors gradually increases to counter for the continual presence of the drug of abuse
- the amount of neurotransmitter gradually decreases through depletion and feedback inhibition
- the reinforcing properties of the drug are thus gradually decreased (tolerance)
- the need for drug to maintain this new homeostasis is therefore increased (dependence begins)
Name the two dominant decision-making centers in the brain.
- Prefrontal cortex
2. Amygdala NAc
State the role of genetics in the development of addiction.
- inheritability has been found to range from 40-60%
- some variability between: gender and substances
- specifically:
- 4-fold increased risk in 1st degree relatives
- 4-fold increased risk also in adopted away children
State why males are more prone to addiction in adolescence.
- the back of brain matures first…
- sensory and physical activities favored over complex, cognitive-demanding activities
- propensity toward risky, impulsive behaviors
- group setting may promote risk taking
- poor planning and judgment
What 2 medications are used to maintain alcohol abstinence in those who have withdrawn from it?
- drug
- function
Naltrexone
-blocks mu opioid receptor (reduces the rewarding effects of alcohol)
Acamprosate
-inhibits the release of glutamate thus decreasing excitation (withdrawal) that occurs during withdrawal
What medications are useful in maintaining abstinence from heroin?
-function
- methadone
- buprenorphine
*they activate opioid receptors
What medications are useful in maintaining abstinence from tobacco?
-function
- nicotine gum/patch
- varenicline (Chantix)
*they activate nicotinic receptors
Explain the multiple dimensions involved in developing addiction.
- addiction is influenced by many factors including biological (neurobiology), social (family, friends, work) and personal (psychological processes relating to addiction)
- while the potential for addiction is related to neurobiology in some degree, situational (social circumstances) factors play a substantial role
- many people use alcohol and drugs and do not become addicted
