Addiction Flashcards
define substance abuse
a maladaptive pattern of use of a drug, alcohol or other chemical agent indicated by continused use despite knowledge of having a persistent or recurrent social, occupational, psychological or physical problem. this pattern is caused or exacerbated by the use of the drug in situations in which it is physically hazardous
define dependance
is a cluster of physiological, behavioural and cognitive phenomena in which the use of a substance or a class of substances takes on a much higher priority than other behaviours that once had greater value. a central descriptive characteristic of the dependence syndrome is the strong desire to take psychoactive drugs
define addiction
is a chronic disease characterised by drug seeking and use that is compulsive or difficult to control,despite harmful consequeces. the initial decsion to take drugs is voluntray for most people, but repeated drug use can lead to brain changes that challenge an addicted persons self-control and interfere with their ability to resust intense urges to take drugs
what does the reward system give motivation to do?
feeding, drinking and sexual coupling
what other substances activate the reward system?
alcohol and other substances of abuse
what system underlies the actions of drugs such as morphine, heroin, cocaine and alcohol?
the brain reward system
what abused substances can lower brain-stimulation reward thresholds?
psychostimulants
opioids narxotics
general CNS depressants
mixed class agents with some psychedelic properties
what are the sites that produece the most vigerous ICSS responding?
lateral hypothalamus
medial forbrain bundel
substantia nigra
ventral tegmental area
where in the brain has the highest conc of DA neurons?
substantia nigra and ventral tegmental area
what increases the release of DA?
stimulation of SN and VTA
What pathways makes up the dopaminergic system?
mesolimbic pathway
nigrostriatal
mesocortical
tuberoinfundibular
what does the mesolimbic pathway do?
VTA to NAcc, the amygdala, the hippocampus and the mPFC
what does the nigrostriatal pathway involve?
substantia nigra with the striatum
what does the mesocortical pathway involve?
VTA to cingulate and frontal lobes
what does the tuberoinfundiubular pathway involve?
arcurate nucleus of the mediobasal hypothalamus to the infunbular region.
what is the brain reward circuit?
consist of interconnected nuclei that have been shown to be involved in the processing of drug reinforcement
what does the VTA do?
respond to stimuli and cues that indicate presence of a reward
release DA signals to the na either directly or indirectly
what does the NAcc do?
important part of the ventral striatum
sends projections to basal ganglia and VP
what does the ventral palladum do?
located in the basal ganglia
recieved dopaminergic imputs from the VTA
what does the orbitofrontal cortex do?
implicated in executive function
involved in complusive drug seeking ad relapse
what does the anterior cingulate gyrus do?
serves as a central hb in addiction related neural networks of cognitive function
how does physical dependence occur?
neurons adapt to the repeated drug exposure
what are some non-addiive drugs that can also produce dependence?
insulin
what are some non-addictive drugs that can also produce withdrawl symptoms?
b3-adrenergic antagonists,clonidinne and tcas
what does psychological dependence refer to?
strong compulsion or desire to experience the effects of a drug
produces pleasures or reduces pyschic discomfort
define drug abuse
refers to a person that uses a drug in doses or ways that result in adverse consequences
define addiction
refers to the state in which both physical and psychological dependence is present
define withdrawl
psychological and physiological reactions to abrupt cessation of a drug that produce dependence
define rebound
is the emergence or reemergence of symptoms that were either absent or controlled while taking a medication, but appear when that same medication is discontinued or reduced in dosage. the symptoms come back in an exaggerated fashion
define relapse
refers to the recurrence of the origional condition from which the patient suffered upon discontinuation of an effective medical treatment
what is tolerance?
state of progressively decreasing responsiveness to a drug
what are the mechanisms of tolerance
pharmacokinetic/metabolic
pharmacodynamic or functional
behavioural tolerance
