Motivated behaviour: Addiction and drugs of abuse Flashcards
What are examples of drug misuse in a healthcare setting?
Examples of drug misuse include prescribing a drug for the wrong indication, wrong dose, or for too long a period (e.g.,benzodiazepines).
How do we know if someone is dependent on a drug?
Dependency on a drug is indicated by withdrawal symptoms that occur when the drug is stopped, which can be physical and psychological.
What are some physical symptoms of drug misuse and how long do they usually last?
Physical symptoms include anxiety, insomnia, nausea, vomiting, muscle cramps, tachycardia, piloerection, and diarrhea. These symptoms usually last 4-6 weeks.
What are some psychological symptoms of drug misuse and how long do they usually last?
Psychological symptoms include anxiety and compulsive behavior. These symptoms can last much longer than physical symptoms, potentially a lifetime.
What are the variables of drug dependence?
The variables include a drug variable (degree of reward), a user variable (absorption/metabolism influenced by genetics), and an environmental variable (peer pressure).
What are the two types of tolerance?
The two types of tolerance are innate tolerance and acquired tolerance.
What is innate tolerance?
Innate tolerance is genetically controlled; fast metabolizers of a drug will be relatively tolerant to it.
What are the different types of acquired tolerance?
Types of acquired tolerance include behavioral tolerance, metabolic tolerance, and pharmacodynamic tolerance.
What are classes of drugs we can become dependent on?
Classes of drugs include opiates, stimulants, MDMA, cannabis, and sedatives.
What are examples of opiates?
Examples of opiates include heroin, morphine, and pethidine.
How can opiates be delivered into the body?
Opiates can be delivered via IV injection or smoking, both allowing rapid increase of plasma levels.
What are the effects of opiates?
Opiates produce a ‘rush’, carry a risk of injectable infections, and can lead to rapid tolerance and high reward due to dopamine release.
What causes the rapid tolerance to opiates?
Rapid tolerance is due to increased expression of adenylyl cyclase, continuing to produce cAMP.
What is the rewarding process of a drug?
The rewarding process involves facilitation of dopaminergic neurotransmission in the mesolimbic dopamine system.
Where are the opiate receptors located?
Opiate receptors, particularly the mu opiate receptor, are located on inhibitory GABAergic interneurons within the ventral tegmental area.
What is the function of the mu opiate receptor?
Mu opiate receptors inhibit adenylyl cyclase, reducing levels of cAMP, which inhibits neurons.
What happens when mu opiate receptors are activated?
Activation inhibits GABA release, leading to disinhibition of dopamine neurons and increased dopamine neurotransmission.
How is opiate overdose treated?
Opiate overdose is treated with naloxone, an antagonist at the opiate receptor, requiring repeated administration due to its short half-life.
How is opiate dependence treated?
Treatment is difficult; methadone is used as it reduces heroin’s effects and has a longer half-life, easing withdrawal.
What are examples of stimulants?
Examples of stimulants include caffeine, cocaine, and amphetamine.
What are symptoms of caffeine withdrawal?
Caffeine withdrawal can cause lethargy, irritability, and weekend headaches.
Describe the pharmacology of caffeine.
Caffeine is a phosphodiesterase inhibitor, increasing cAMP levels and neuronal activity.
What are the secondary pharmacological effects of caffeine?
Caffeine acts as an adenosine receptor antagonist, enhancing neuronal activity and acting as a diuretic.
Where does cocaine come from?
Cocaine is derived from coca leaves.
