Mechanism of Reinforcement/abuse of drugs
Correction of deficient endorphin or reinforcement system
Need to continue use due to downregulation of endorphin or reinforcement system
Positive reinforcement in drug abuse
Increased release of DA in the nucleus accumbens (mesolimbic pathway)
Negative reinforcement in drug abuse
gradual dependence of alleviation of preexisting dysphoria or painful states (self-medicating)
Associative learning/conditioning in drug abuse
drug effects & withdrawal become linked w/cues & mood states
bind to opioid receptors and relieve pain (analgesia)
Activation of which receptor has the strongest analgesic effect and most abuse potential?
What is the second most abused illicit drug?
Rx opioid analgesics
What is the 1st most abused illicit drug?
Acute effects of alcohol abuse
executive disinhibition extremely poor judgment MVA's date rape unprotected sex spousal or child abuse aggression crime death
Alcohol represents time out from the usual rules of daily behavior that govern behavior
When intoxicated, local and immediate cues govern behavior
T or F: alcohol has both positive and negative reinforcing effects, which explains some addictive potential.
What are the positively reinforcing effects of alcohol use?
increase of DA release in the mesolimbic pathway by stimulating opioid and cannabinoid receptors on DA neurons in VTA, thereby reinforcing and increasing craving
What are the negatively reinforcing effects of alcohol use?
It’s anxiolytic, causing CNS inhibition/depression by enhancing GABAA and inhibits NMDA-Glu receptors
Fetal Alcohol Syndrome (FAS)
Small brains, learning disabilities, low IQ’s, hyperactivity, physical abnormalities
What is the active ingredient in marijuana obtained from cannabis sativa
Delta-9 tetrahydrocannabinol (THC)
What receptor does THC act on?
an endocannabinoid that plays a role in forgetting so that the brain is not overwhelmed with information
Acute effects of MJ at usual doses
Relaxation, sense of well-being, friendliness, sense of having special insights
Loss of temporal awareness (time estimation, confusion, past w/present); slowed cognitive processing; impaired selective & divided attention, short-term memory, cognitive flexibility
Acute effects of MJ at toxic doses
panic, delirium, paranoia, psychosis
Effects of chronic, heavy (daily) use
- shortened attention span, distractibility, impaired judgement, short-term memory deficits (which may persist after use)
- Hypomotivational syndrome, impaired communication & interpersonal skills, introversion, loss of insight, feelings of personalization
What impact does chronic MJ use have on patients at risk for schizophrenia?
- precipitation of ill,ess
- lower age of onset
- exacerbate current illness
What are some of the positive benefits of using MJ?
- May suppress appetite and reduce pain sensitivity
- May lower BP, reduce nausea and decrease intraocular pressure in glaucoma