Drugs and The Brain - Understanding Addiction

• Drugs come from plants either as by-products of them or developed chemically.
• In the US, $150 billion is spent on legal pharmaceutical drugs.
• All pharmaceutical drugs have at least three names.
  • chemical name of a drug is the organic chemistry chemical description of the molecule.  Most will never know or understand this name of a drug they are taking.
  • generic name of a drug is the official name of the drug.  It is still a detailed chemical name but much simpler.
  • brand name is for a specific formulation and manufacturer.
• The big difference between the generic name and the brand name is that a generic name is public domain while a brand name is trademarked by the company that developed the drug.  The developing company gets to name the drug but it must be FDA approved.
• One drug can be a painkiller, a controlled substance, a schedule II substance or just morphine.
• Categories of psychoactive drugs are:
  • stimulants
  • hallucinogens
  • marijuana
  • depressants
  • opioids
  • psychotherapeutics
  • nicotine.
• All drugs have defining characteristics.
• The Physician’s Desk Reference has color photographs of most legally manufactured drugs; it also includes information like dose and potency.
• The placebo effect is usually thought of in terms of a sugar or fake pill.
• Many drugs effects are influenced by the users experiences, mood, how tired they are, in addition to other substances in the system, such as food to other drugs.
• Dose-response refers to the correlation between the response and the quantity of drug administered.
  • The response may vary due to factors such as tolerance.
  • With a dose-response curve we hope to be able to answer a verity of questions; from what is an effective dose or a lethal dose.
• Toxicity, in early animal studies, is measured in how many animals die as a result of taking the drug.  After more studies, the therapeutic index is set as LD50 / ED50.
• The margin of safety is the difference between doses necessary for an intended effect and toxic unintended effects.
• Potency refers to the amount of drug necessary to cause an effect, while toxicity is the capacity of a drug to upset or destroy normal body functions.
• The forms and methods of taking drugs greatly effect how the drugs will interact with the users system.
  • Oral ingestion is the simplest way the drugs enter the body, but also the most complicated way to enter the bloodstream. Oral ingestion must make it through the acid in the stomach while avoiding neutralization by food and drink.  When the drug gets past the stomach it still has to go through the liver, as well as other organs.
  • Inhalation is when the drug is smoked or “huffed”.  Nicotine, marijuana, crack are most effective when delivered this way.   It is also rapidly absorbed due to all the capillaries in the lungs consequently moving quickly into the blood.  This is the fastest way to get psychoactive drugs into the system.
  • Injection put the drug into the system as well.
    • Intravenous injection puts the drugs right in the vein, so the onset of the effect of the drug is fast.  You can so put a high concentration of drugs in because it does not have to pass through a membrane.
    • Intramuscular injection puts the drug into the muscle and subcutaneous goes just under the skin.
  • Topical application is not used as often because many drugs are not absorbed effectively through the skin.
• After drug administration, the body eliminates the drug through metabolism and excretion.
• The drug will either leave the system or be changed so much that it will no longer have an effect on the body.
• Prodrugs have been developed to start working only after they have been altered by the body.
• The body has adaptive processes such as tolerance and dependence to protect against potential harm.
• With drug disposition tolerance the more the drug is used the faster the metabolism or excretion.
• Behavioral tolerance (conditioned tolerance) is when the behavior of the user changes even if the bio-chemical reaction in the body does not. There is strong evidence that tolerance effects are maximized when the drug-taking behavior occurs consistently in the same surroundings or under the same circumstances.

Today's Society &

Drug USe

• Drug use is taking an aspirin for a headache, or a single dose of cough syrup for a cough or a hit of acid.
• How the drug is taken has an effect on how the body reacts.
• How much and how often are points that make the difference between normal use and abuse.
• Four principles of psychoactive drugs:

1. Drugs are not bad or good; they are not evil, they are a substance. By itself a drug cannot do anything until it enters a body. Some drugs help the body function when taken correctly but can cause harm when misused or abused.
2. Every drug has multiple effects. No part of the body works independently from the rest; all systems are connected. When a drug is taken it affects all parts of the body it passes through.
3. Both size and the quality of the drug affect the effects of the drug. The better the quality, or the larger the dose the larger the response or the more severe the response.
4. The effects of a drug depend on the person. Not only personality, but age, race, weight… all  of them influence how the body takes in and responds to the drug.

• History tells us that humans have used, misused and abused some plants or substances for as long as humans have been around.
• Four pharmacological revolutions

1. 19th century – vaccines. This is the first time drugs were used to help stop the number one killers at the time: communicable diseases. For the first time there were drugs that were powerful and have selective beneficial effects. This helped people have faith in medicine stopping illness.
2. WWII – antibiotics. Not only did they help cure diseases but also helped prevent infection. This got us to the point that we are now; we expect to take something to fix everything.
3. 1950’s – anti-psychotic drugs. This was the first time that drugs were used to treat psychotic disorders. This changed the way people saw and treated mental illness. We have new drugs that effect how we think, our emotions, and perceptions.
4. Oral contraception – now we have control of our body through chemicals. Some drugs are not meant to treat anything but to control and change the way the body was meant to work.

• Then there were many social changes in the US: The Beatles, civil rights, Vietnam, LSD, etc. Drugs became more common and accepted.
• In 1971 Nixon declared the first “War on drugs”; yet during this time the legal drinking age was lowered and penalties for having marijuana were eased.
• In the 80’s tolerance lessened. The legal drinking age was raised to 21 again and penalties were stiffened on all drugs, including marijuana.
• Perception of the risk – when the perception of the risk is low the use is high and vice versa. This differs from perception of availability.
• Longitudinal studies are one way we have looked for antecedents of drug use.
• Evidence tells us not to do things but we do them anyways; from eating too much, driving too fast,drinking too much, texting while driving, and driving while intoxicated
• Cultural trends influence what drugs are being used.