exam 3 Flashcards
controlled substances act (CSA)
categorizes drugs “based upon the substance’s medical value, harmfulness, and potential for abuse or addiction
drug addiction emphasized the importance of ___
physical dependence
not all drugs of abuse induce withdrawal symptoms such as:
cocaine so this was not considered an addictive drug because it lacks and opiate-like withdrawal syndrome
addict is often driven by a strong urge:
craving
substance dependence
the more severe disorder, corresponds roughly to the notion of addiction
substance abuse
less severe disorder that may or may not lead subsequently to substance dependence
- the mere use of any drug does not constitute substance abuse or dependence
- according to the DSM the use must be maladaptive (harm is occurring to the user).
addiction is NOT:
- experimental drug use
- recreational (casual) use
- circumstantial use
CNS stimulants
- amphetamine
- cocaine
- nicotine
CNS depressants
- barbiturates
- alcohol
- inhalants
- benzodiazepines
analgesics
- morphine
- codeine
hallucinogens
- mescaline
- LSD
- psilocybin
- PCP
- Ketamine
tolerance
decrease in potency with repeated administration of same dose
cross-tolerance
tolerance to one drug in a class confers tolerance to others in that class
dependence
withdrawal symptoms when drug use is terminated
addiction/substance dependance
persistent use, even in the face of physical, psychological or social harm
physical dependence model
- initial drug use
- repeated drug use
- physical dependence
- attempts at abstinence
- withdrawal symptoms
- drug seeking behavior through a process of negative reinforcement.
- relapse
disease (medical) model: susceptibility
addicts are born not made
- initial drug use > repeated drug use > loss of control
disease (medical) model: exposure
chronic drug use leads to alterations in the brain responsible for loss of control and the other key features of addictive behavior
initial drug use > repeated drug use > altered brain function > loss of control
ventral tegmental area
nucleus accumbens dopamine system is strongly implicated in mediating drug reward
mesolimbic dopamine sytem
activated by rewarding stimuli eg food, sex and by addictive drugs, such as cocaine, amphetamines, and alcohol
hippocampus and amygdala
responsible for memories of pleasure - people, places and activities associated with use
prefrontal cortex
impairments mediate long-term changes involved in loss of control, relapse
how do we know dopamine is released
- natural reinforcers release DA
- block the DA receptors; reduce reinforcing effects
- destroy DA cells; animals stop working for cocaine
- DA blockers are not abused
repeated drug use may develop into chronic drug use that can become compulsive and result in addiction
- frontal lobe is profoundly altered by chronic drug abuse
- cortical hypo frontality
- fewer dopamine receptors in the NAc than normal and lower metabolic rate in the frontal lobe
hypotrontality develops with chronic use
- reduced activity of frontal cortical structures
- normally, these structures control executive functions through glutamatergic projections back to the NAc and VTA
- brain of a cocaine user shows reduced metabolic activity of frontal lobe compared to that of a non-user
decreased dopamine in addicted brains
brain images showing decreased dopamine (D2) receptors in the brain of a person addicted to cocaine versus a nondrug user
the dopamine system is important for conditioning and motivation and alterations such as this are likely responsible in part for the diminished sensitivity to natural rewards that develops with addiction
as a result of chronic drug use, natural rewards become _____ pleasurable and release less dopamine despite _______ _____ in dopaminergic transmission than normal
less; greater response
frontal cortex becomes inherently ____ active and less responsive to normal rewards, but it is ______ in response to drugs or stimuli that predict drugs
less; overactive
memory of positive effects of a drug provides the motivation for compulsive use, and is believed to be responsible for relapse
this memory is mediated by the amygdala and hippocampus
over time, stimuli that “predict” drugs produce a greater response in the ___ pathway than the rewarding stimuli themselves
reward
such conditioned or learned responses could elicit powerful _____ sensations in the frontal cortex
craving
