EXAM #3 STUDY GUIDE (Part 1)
Chapter 9: Drug Abuse and Addiction
Addiction: Addiction is complex, and a precise definition is difficult. It can include:
Physical dependence: abstinence leads to highly unpleasant withdrawal symptoms that
motivate the person to return to drug use
Addictive behavior: the addict is driven by drug craving – a strong urge to take the drug
Individuals remain addicted for long periods of time, and drug-free periods (remissions) are
often followed by relapses in which drug use recurs (despite negative consequences)
The latest American Psychiatric Association’s Diagnostic and Statistical Manual of Mental
Disorders (DSM) DSM-5 defines addiction as substance use disorder:
The individual has manifested a maladaptive pattern of substance use for at least 12
months that has led to significant impairment or distress, by clinical standards.
The mere use of a drug does not constitute a substance use disorder; drug use must be
maladaptive (causing harm to the user) to qualify as a disorder Factors contributing to the addictive potential of a drug:
Route of Administration
Speed of Onset
Duration of Action
Fast onset is associated with shorter duration of action and is more likely to produce addiction.
Oral or transdermal administration results in relatively slow absorption of the drug
Intravenous (IV) injection or inhalation/ smoking yields rapid drug entry into the brain and fast
onset of drug action, and produce the strongest euphoric effects as a result of rapid drug
delivery to the brain
Repeated exposure to rapid delivery may produce long-term neurobiological changes
contributing to the development of addiction
The Role of Associative Learning in Drug Addiction
Abused drugs act as positive reinforcers; consuming the drug strengthens the probability of
repeating whatever preceding behavior was performed.
Drug reward refers to the positive experience associated with the drug.
Substances that are strong reinforcers when taken intravenously or inhaled have strong abuse
potential: cocaine, heroin, amphetamine, and methamphetamine.
Animal models of drug addiction
Drug reinforcement is studied by investigating how animals self-administer the drug.
Relapse is modeled in self-administration studies by forcing abstinence, then reintroducing
stimuli known to provoke renewed responding:
1. Delivering a small dose (drug priming).
2. Subjecting animal to stress. 3. Exposing animal to environmental cues (conditioned stimuli) previously paired with drug
Self-administration of a drug by research animals provides a measure of addictiveness of drugs
Electrical self-stimulation of the brain’s reward circuit on performing an operant response; the
threshold is reduced when animals have been treated acutely with drugs of abuse.
Place conditioning: animal associates one compartment with rewarding effect of a drug.
Withdrawal / Abstinence
Abstinence syndrome - Attempts at abstinence lead to highly unpleasant withdrawal symptoms,
which motivates the user to take the drug again
“Impulsive” stage of drug use – primary motivation is the substance’s positive reinforcing
”Compulsive” stage of drug use – primary motivation is the negative reinforcement obtained by
relief from drug withdrawal
The withdrawal response can become classically conditioned to the stimuli associated with the
environments in which withdrawal occurs; Withdrawal symptoms, such as craving, can then be
triggered by exposure to the conditioned stimuli
The Role of Genetics, Personality Traits, and Mental Health
Genetic variation may also contribute to vulnerability to addiction; individuals who carry specific
alleles of genes are at increased risk of developing substance abuse disorders.
In alcoholism and tobacco addiction, susceptibility genes include those coding for enzymes
involved in alcohol or nicotine metabolism. Receptors for dopamine (in the case of alcoholism) or acetylcholine (for nicotine) have also been
Psychosocial variables also contribute to addiction risk: Stress and the ability of the person to
cope with stress, treatment often includes learning new coping skills.
Anxiety, mood, or personality disorders; co-occurrence with addiction is called comorbidity.
Self-medication hypothesis: Stressful life events could trigger anxiety an