Chapter 15 - Drug addiction & the brain's reward circuits

Chapter 15 - Drug addiction & the brain's reward circuits

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Basic principles of drug action Commonly abused drugs Bio-psychological Theories of Addiction 15.1 Basic principles of drug action Psychoactive drugs – drugs that influence subjective experience & behaviour by acting on the nervous system Drug administration – route of administration influences the rate at which & the degree to which the drug reaches its site of action Oral ingestion – oral route o o Absorption via digestive tract is unpredictable Injection – bypasses digestive tract o Subcutaneously (SC) – under the skin o Intramuscularly (IM) – into large muscles o Intravenously (IV) – into veins, drug delivered directly to brain o Absorbed through capillaries in lungs Absorption through mucous membranes o Mechanisms of drug action Psychoactive drug must pass through blood-brain-barrier to be effective Liver enzymes terminate actions of drug – drug metabolism Drug Tolerance Decreased sensitivity to a drug as a consequence to exposure to it o Shift in the dose-response curve to the right Cross tolerance – exposure to one drug can produce tolerance to similar drugs o More than one form of tolerance Metabolic – less drug is getting to the site of action Functional – decreased responsiveness at the site of action; fewer receptors; decreased efficiency of binding at receptors, receptors less responsive 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Withdrawal Seen when drug use is terminated Symptoms are the opposite of the drug’s effects Body has made changes to compensate for drug’s presence – functions normally with the drugs present Addiction “Addicts” are those who continue to use a drug despite its adverse consequences While they may re-occur, each can exist independently 15.2 Role of learning in drug tolerance Contingent drug tolerance o Tolerance only develops to drug effects that are experienced Conditioned drug tolerance
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/27/2010 for the course PSYCHOLOGY SPC 211 taught by Professor Ms.chitra during the Spring '10 term at Sunway University College.

Page1 / 6

Chapter 15 - Drug addiction & the brain's reward circuits

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online