Drug Addiction Flashcards
Antidepressants and antipsychotics cause withdrawal effects (rebound phenomena) if suddenly discontinued Are they addictive?
No.
Dependence isn’t neither necessary nor sufficient for addiction. With these drugs there’s neither. Just “rebound phenomena”.
Six signs of dependence (only three required for diagnosis:
Four are just variations on “wanting the drug”
COMPULSION, strong desire to take the drug PREOCCUPATION with the substance WITHDRAWAL symptoms when stopped TOLERANCE (evidence thereof) PERSISTENCE DESPITE HARM DIFFICULTY CONTROLLING habits
What four signs of dependence are just variations of wanting it?
COMPULSIVE desires to take it
LACK OF CONTROL over habits
DESPITE HARM continuing habits
PREOCCUPATION with taking them
Easy:
What are the two facets that drive addictive behaviour?
Negative reinforcement: tolerance and withdrawal
Positive reinforcement: the drug feels good.
You get to the addicted stage through “_________”. Withdrawal is seen as a manifestation of this.
habituation.
What pair of molecules are involved in the physical dependence of morphine addiction?
Morphine inhibits ADENYLATE CYCLASE, leading to less cAMP.
Adenylate cyclase is UPREGUATED, potentiating withdrawal symptoms.
When normal adenylate cyclase activity returns, cAMP goes nuts, creating withdrawal symptoms.
What is upregulated (due to inhibition) during opioid use, leading to withdrawal symptoms?
adenylate cyclase
How is adenylate cyclase involved in morphine physical addiction?
Is inhibited by morphine, gets upregulated, potentiating a cAMP storm upon discontinuation.
Which is usually seen as a more compelling reason for addiction - physical dependence or psychological reward?
Psychological reward.
Key: the quicker the onset, the more addictive potential.
e.g. the slow onset of morphine tablets versus the intense high from mainlined heroin.
DELIVERY is a better predictor than pharmacodynamics.
Bonus: Explains difference between heroin and morphine, why quicker onsets raise addiction rates (without affecting adenylate cyclase)
The mesolimbic [dopaminergic] pathway runs from the ________ to the __________.
ventral tegmental area (VTA) to the nucleus accumbens.
The thing leading from the VTA to the nucleus accumbens is called the…
mesolimbic pathway.
What leads to the nucleus accumbens, forming the mesolimbic pathway?
The ventral tegmental area.
What three structures are in the ADDICTION lecture?
Mesolimbic pathway
Ventral tegmental area
Nucleus accumbens
What two structure are involved in the ANTIPSYCHOTICS lecture?
Nigrotrial pathway (substantia nigra to the striatum)
EPS
Mesolimbic pathway
antipsychotic effects
Bonus: mesocortical - aripiprazole partial D2 agonism.
What other two neurotransmitters receive a mention?
5HT and glutamate.
