Psych of drug use and abuse Flashcards
(97 cards)
Learning
a permanent change in behavior as a result of experience. Drug use and addiction are learned behaviors because people aren’t born addicted to certain drugs
Genetic component of addiction
People can inherit certain genes that make them more or less susceptible to addiction- but you can’t be addicted to something without ever taking it. Infants can be born with a drug dependence (not addiction) if moms take drugs during pregnancy
When you take a drug or medication repeatedly, what happens in your body? (3)
- You learn how to administer it
- Your body gets better at processing it (tolerance)
- Your body starts to anticipate delivery of the drug and prepare for it- your body wants to maintain homeostasis- craving and withdrawal
Mithridates VI (king of Pontus)
A historical example of tolerance. The king had spent his life afraid of being poisoned. Throughout his life, he took increasing doses of well known poisons and his body learned how to metabolize the drugs. The king later attempted to take his own life by ingesting poison, but it didn’t work due to tolerance.
Tolerance
Decreased effectiveness or potency of a drug after repeated exposure. You need to use larger doses of the drug to achieve the same effects as when you first took it. Typically, tolerance occurs with drugs that are really disrupting homeostasis
Do you develop tolerance to all of a drug’s effects at the same rate?
No. One example is morphine and other opioids. Nausea and vomiting is a common symptom- tolerance occurs very quickly, after only a few administrations. You can’t develop tolerance toward constriction of pupils, however- this symptom will occur during every administration. It is a physiological effect that won’t go away.
Cross tolerance
Sometimes tolerance to one drug will diminish the effect of another drug- this usually occurs between the same class of drug. All opioid drugs show cross tolerance. If you develop a tolerance to heroin, you will also have tolerance toward oxycodone and morphine. This suggests that these drugs are producing their effects by common mechanisms.
Why can cross tolerance potentially be dangerous?
For opioids, cross tolerance can be problematic. A person may eventually be in a situation where they are very sick or badly injured and need these drugs to work to reduce their pain
Pharmacokinetics
Refers to how drugs move throughout the body. This concerns how a drug is administered and how it is absorbed into the bloodstream, reaches different parts of the body, and is eliminated from the body
Pharmacodynamics
Refers to how drugs cause biological changes in the body. Deals mostly with the actions of drugs at synapses
Absorption
The passage of a drug from the site of administration to the bloodstream. To do this, a drug must pass through different membranes, like the mucous membranes in the mouth or the walls of the intestines. The specific membrane the drug has to pass through depends on the drug’s route of administration.
Administration routes and speed of drug absorption
The route of administration determines how much drug reaches the bloodstream and the length of time needed for drug absorption. When administered intravenously, peak occurs in the blood almost immediately and then diminishes quickly as it’s processed by the body. With inhalation, the peak occurs and drops off very quickly, but not as quickly as IV use. By mouth routes takes the longest to peak and therefore has less potential for addiction.
Elimination
The process by which a drug leaves the body. This can be through urine, sweat, saliva, and breath. The specific route of elimination depends on the drug. Alcohol is one example of a drug that is mostly eliminated through the breath
Pharmacokinetic tolerance
A type of tolerance that occurs as the body becomes more efficient at metabolizing a drug- your body gets better at metabolizing the drug over time. When you experience pharmacokinetic tolerance all effects of the drug are diminished. Someone who frequently drinks hard liquor will be producing enzymes to break down the alcohol before they even start drinking. Someone who is well practiced at drinking will have a lower blood alcohol level than someone who doesn’t typically drink since they are better at breaking down the drug
What changes can occur in the body with pharmacokinetic tolerance? (3)
- Fewer drug molecules reach their sites of action
- Increase of enzymes the body uses to break down the drug- the drug is more quickly converted to metabolites so fewer molecules of the drug remain
- Drug does not reach the same peak levels and doesn’t last as long
Pharmacodynamic tolerance
Reduced responsiveness to a drug at the drug’s site of action. This arises from adjustments made by the body to compensate for effects of continued presence of a drug. It is a result of the body trying to maintain homeostasis. With this type of tolerance, there can be a change in the number of receptors available for the drug
Upregulation
Refers to an increased number of receptors for a drug
Downregulation
Refers to a decreased number of receptors for a drug
When a person first ingests a drug, what happens? (3)
- Detects the drug and the effects on homeostasis- often the hypothalamus
- Responds by compensating to restore normal functioning
- Over time- the body gets better at restoring normal functioning
How does the compensatory response change when a person stops taking a drug?
When you take a break from using a particular drug, the compensatory process weakens and you have more of an effect from the drug if you take it again. When you go through withdrawal multiple times, your body also gets better at going through withdrawal and processing that compensatory response
Behavioral tolerance
Decreased behavioral responses to a drug. You learn to function while impaired on a drug, and the drug has less of an impact on your behavior. It doesn’t necessarily mean you can still do activities as well as you would sober. A doctor with an alcohol use disorder can still perform surgery, and a person addicted to marijuana can still get a good grade on an exam
State dependent learning
Someone who is dependent on a substance and studies while under the influence will do worse on an exam if they try to take it sober. The fully sober test takers still perform better overall
Tolerance only develops in which situations?
Tolerance develops (or develops quickly) only when a drug places a demand on homeostasis- tolerance will not be generated if the drug is not detected or does not disrupt function. Pain is one example- it is unpleasant but still really useful for survival. Tolerance to morphine develops much faster when rats experience pain following injection- when morphine is given in the presence of a painful stimulus
Withdrawal
Physiological and psychological changes that occur when drug use stops. These symptoms are due to compensatory mechanisms to maintain homeostasis when the body expects the drug. Can be quite mild or quite intense (can cause death). The level of danger of withdrawal depends on the level of dependence. Death can occur from withdrawal from alcohol and heroin/opioids. Withdrawal from alcohol is probably so dangerous because alcohol is very available in everyday life and more socially acceptable to consume- people generally consume much higher amounts