Chapter 8 Drug Abuse

Data on illicit drug use Survey of population in US age 12 and older for illicit drug use About 8% of pop currently uses illicit drugs of different kinds (note alcohol, tobacco not included here), early 20s most frequent users Most people who use illicit drugs use marijuana Lots of drug use in our current society But this is not really new, psychoactive drugs have always been part of most societies Esp. alcohol, nicotine, caffeine, morphine

Two developments important for explaining today’s drug use Heroin in cough medicine Two important aspects which changed drug use in US: - Developments in chemistry enabled us to extract active ingredients, increase concentration and thus increase likelihood of addiction - Invention of hypodermic needle (better method of delivery) But how to tell if any of this use is problematic? What is drug abuse? Difficult come up with a satisfactory definition

Patterns of opioid drug use over a 20-year period in ten heroin addicts Even more confusing, this graph shows that there a lots of different patterns of drug use that people can take Some with periods of abstinence, others with alternations of drugs heavy use alternating with occasional use

Continuum of drug use Continuum of drug use: Abstinence – no drug use Initial experimentation – first time use Some people never use drug again Some people continue to use drug occasionally Some of them eventually stop use altogether (abstinence) Eventually some people develop substance abuse problems (less severe, basically tolerance, withdrawal formed, use more than you mean to) Point at which drug use becomes problematic is difficult to pin-point (arrow in between non-problem use and substance abuse) Some drugs will also cause substance dependence (more severe, all of substance abuse plus major problem with job/family, physical safety, legal problems) Two ways that drug use could be: Changing amount of use or pattern of use (red line means that they are moveing away from problem behavior) Changing type of drug used Why do some people get addicted to a drug but not others?

Models of Drug Abuse The physical dependence model of addiction Early views defined it as use whose stop leads to physically unpleasant effects (ex. alcohol – delirium tremens - state of confusion and hallucinations, convulsions, nausea, insomnia; opiates - nausea and vomiting, diarrhea, hot and cold chills, insomnia, panic) So once person gets physically dependent on a drug, they may try to stop use, but withdrawal symptoms are too severe and cause a relapse

Which drugs are more addictive? High addictive potential called hard drugs One way of classifying: Withdrawal – presence and severity of physical problems when a person ceases to use a frequently used drug 1 – most addictive; 6 – least addictive Most addictive according to this criterion alcohol, heroin, nicotine

Problems with model: 1. 2. 3. Problems with model: - Some major drugs of abuse have no withdrawal like cocaine (which is why it was at one time considered non-addictive) - Doesn’t explain how dependence came about to begin with How to explain why person goes back to drug after withdrawal over?

Withdrawal and explaining continued drug use Negative reinforcement Why does a person continue to use drug after withdrawal is over? Proposed idea involves learning and negative reinforcement After someone has developed a physical dependence on a drug, they will experience withdrawal when they stop taking the drug During this experience of withdrawal: levels of drug in body fall (US)  withdrawal symptoms (UR) if person goes thru several withdrawals, they start associating certain environmental cues (CS) and feelings of withdrawal (CR) Eventually those cues themselves can cause feelings of withdrawal (esp. cravings) Next part operant conditioning… To get rid of feelings of withdrawal, person will take drugs again (negative reinforcement – removing something to increase a behavior)

Different ways of trying to understand drug dependence Other ways to define abuse concentrate on behavior: Compulsive nature of use Periods of chronic use Use persists despite harmful consequences to user According to DSM-IV, drug dependence is… Three or more of the following: Tolerance Withdrawal Large amounts or longer period than intended Desire or effort to cut down use Lots of time used to use drug, get drug, or recover from effects Important events reduced or given up Use continues despite knowledge of a problem

Drug abuse is… Pattern of use leading to impairment of role obligations, places where use is dangerous, legal problems, or social problems

Models of Drug Abuse The positive reinforcement model of addiction Model 2: pos reinforcement (all operant this time) Person takes drug, feels euphoric, person wants to feel like that again, so keeps taking drug (positive reinforcement – adding something to increase behavior) Explains why a person gets started using drug Presumed mechanism in brain is reward pathway Destroy this pathway and cocaine/amphetamine use does disappear, but heroine, alcohol do not Maybe another mech in brain for reward? Maybe pos reinforcement model not whole story? Other problems? After using first few times, a little craving, but after using more often, cravings get much stronger And yet, the high in each case is exactly the same; in fact, high might even be less after numerous doses Why is there this increase in craving? If simply a matter of reinforcement, there should be no increase In other cases where a reinforcer ceases to have same level of value, behavior usually decreases, not so for drugs -Why does addiction happen to some people but not others?

Models of Drug Abuse The incentive–sensitization model of addiction Difference between liking and wanting a drug

Models of Drug Abuse The original opponent–process model of motivation

Classical conditioning of drug-related cues So whenever person is in same environment, body gets ready for drug by having opposite reaction to offset drug effects, which requires more of the drug to have the desired effect

Models of Drug Abuse An updated opponent–process model of motivation Problems: Don’t explain early experimental stage

Models of Drug Abuse Disease Model of Addiction Sus - Exposure Prob lems: No one blamed for having a disease

Models of Drug Abuse “Gateway” theory of drug use Person starts with legal drugs (alcohol, tobacco), move to marijuana, then to harder drugs like cocaine or heroin (see table of survey of 12th graders) Problems with theory: Usually done with school surveys, where users are generally casual users but is this characteristic of hard-core users, who usually cause most of the problems? (if person is heavy user that usually are not in school) 2. Theory implies that pot use CAUSES other drug use, but most users do NOT progress to other drugs

Models of Drug Abuse Biopsychosocial model (still in development) Reasons for early experimental with drugs Proximal – most influence Ultimate – risk factors

Models of Drug Abuse Biopsychosocial model (still in development) Reasons for later development and maintenance of compulsive drug use Factors Drug-related: mood, relief from negs, enhanced function Risk – stress, mood disorders, social structures and examples, genes Protective -

Which drugs are more addictive? High addictive potential called hard drugs One way of classifying: Withdrawal – presence and severity of physical problems when a person ceases to use a frequently used drug Reinforcing – the ability of a substance or act to increase likelihood of using substance or performing act again in the future (one example, producing pleasurable feelings) Tolerance – decreased response of a drug due to repeated use of the drug (more drug needed to produce same effect as first time it was used) Dependence – degree of difficulty that person has stopping drug use, measured in terms of feelings of yearning, relapse rates, number of people who have trouble quitting use Intoxication – degree of to which a drug can alter one’s physical and mental faculties Most addictive, all categories considered: Heroin (1.9) Alcohol (2.5) Cocaine (2.65) Nicotine (3.35)