Module 2 Section 5 (Drug Dependence and Abuse) Flashcards
Why do people abuse drugs?
Because they gain something from their use. The gain may be an altered feeling, benefits from social interaction, or the thrill of experiencing something new and perhaps risky. The greater the “good feeling” obtained from a drug, the more likely the use of the drug will be repeated. This phenomenon is known as reinforcement.
Why is substance dependence a serious social and financial issue?
It occurs across all social groups, it may lead to crime to financially support the use, and it can lead to illness and death.
What kind of drugs can be classified as substance abuse? (6)
- The use of prohibited drugs.
- The use of any therapeutic drugs for other than its intended use.
- The intentional ingestion of any therapeutic drug in amounts greater than that prescribed, or taking the drug by routes other than those medically approved.
- Taking drugs in combination in order to obtain a greater pleasurable effect.
- The excessive use of licit (legal) social drugs (alcohol, caffeine, tobacco).
- The use of non-therapeutic substances of abuse, including glue (sniffing), gasoline, and solvent
What factors increase the probability of substance abuse?
Genetic factors: genetic factors can predispose an individual to substance abuse.
- Ex: it’s reported that sons of alcoholic parents are at higher risk to become alcoholics than sons of non-alcoholic parents independent of their environment.
Co-existing disorders: individuals with major affective disorder (i.e. depression or bipolar disorder), anxiety disorder, or schizophrenia are at higher risk to abuse substances than the general population.
Environmental risk factors: social environments can have positive or negative influences on the potential for substance abuse.
- Ex: stable family life and social circles can reduce the risk of substance abuse.
Developmental aspect: adolescence and early adulthood are the age groups primarily associated with the initiation of substance abuse.
- Smoking usually begins before the age of 18
- 80% of alcoholics begin abusing alcohol before age 30
- illicit drug use usually begins between 15 and 18 years of age
What are the 3 factors that contribute to the potential for a drug to be abused?
1) Dependence liability: the tendency of the drug to cause dependence and addiction. It varies from drug to drug, as well as from individual to individual, but is determined by three factors:
- Nature of the drug: the pleasurable effects produced by a drug increases the probability that the drug will be taken again. Ex: heroin and cocaine produce intensely pleasurable effects, and therefore have a high intrinsic dependence liability.
- Route of administration: drugs that can be administered by routes that give rapid absorption, and hence rapid effects, have a greater potential for abuse than drugs which produce the effect more slowly. Ex: drugs that are taken by sniffing, by inhalation, or intravenous injection are usually more abuse-prone than those taken orally.
- Amount and frequency of use: the greater the dose and the frequency of use, the greater the potential for development of dependence. Ex: occasional use of alcohol in moderation (social drinking) will rarely lead to dependence, but frequent, high-dose use of alcohol will lead to dependence.
2) Availability: the availability of a drug in society is a major factor in determining abuse potential. The more widespread a drug, the more likely it will be abused. Alcohol, which has only moderate intrinsic dependence liability, is the most highly abused psychoactive substance in our society, largely because it is readily available. Heroin, on the other hand, has very high intrinsic dependence liability, but has posed a lower overall risk in North America as availability is controlled by law and cost.
3) Inherent Harmfulness: the inherent harmfulness of a drug refers to the potential of the drug to cause harm. If a drug is perceived to be a serious risk to life and health, it will not be used, even if widely available. Ex: methyl alcohol (wood alcohol or methanol) is widely available, and when consumed it produces inebriating effects similar to those produced by ethyl alcohol (beverage alcohol). However, methyl alcohol in small doses can cause blindness and death. Hence, methyl alcohol is not commonly abused, even though it is widely available.
What is substance dependence?
Substance dependence is a condition in which the body has adapted to the presence of a drug. It is often cause by repeated consumption of a drug (natural or synthetic).
What 3 important aspects define substance dependence?
From a pharmacological viewpoint, three important aspects define substance dependence: (a) drug tolerance, (b) drug dependence and withdrawal, and (c) drug addiction.
What are the 2 ways drug tolerance is defined?
1) A state in which repeated administration of a given dose of a drug has progressively less pharmacological effect
2) A state in which the dose of a drug must be increased to obtain the same magnitude of pharmacological effect as was produced by the original drug dose
True or false: the biological system accommodates to the presence of the drug.
True
True or false: drug tolerance is usually expressed as shortened duration of action and a decreased magnitude of effect.
True
The extent and rate of development of tolerance is specific for each drug.
- Tolerance doesn’t develop to all drugs, or to all aspects of a drug’s action.
- Drug tolerance is reversible upon drug discontinuation.
- Ex: tolerance develops to the euphoria caused by heroin, but not to the constipating effects caused by heroin.
What are the 2 mechanisms in which tolerance develops?
1) Metabolic tolerance: increased elimination of the drug from the body, usually due to increased drug metabolism.
2) Cellular tolerance: occurs via up- or down-regulation of receptor systems. Under normal circumstances there is a balance between receptor activity and a cellular process. However, repeated administration of a drug can induce cellular tolerance.
True ot false: the normal regulatory mechanisms will increase or decrease the receptor population/transmitter release to maintain a set level of activity.
True
Describe what occurs during cellular tolerance.
1) A drug binds to a receptor on the cell membrane
2) This activates a process within the cell
2) The cell then compares the current activity within the cell to the regular “set-point”, or the set level of activity that is normally maintained within the cell
3) In response, the cell can increase or decrease the number of receptors on the cell membrane, in order to return activity to the genetic set-point
4) When a drug repeatedly binds to a receptor, the genetic set-point increases and cellular tolerance to that drug increases
What is cross tolerance? Provide an example.
Cross tolerance can occur between pharmacologically similar drugs.
Cross tolerance is defined as the resistance or tolerance to one drug because of the resistance or tolerance to a pharmacologically similar drug.
Ex: if a person is tolerant to the CNS depressant alcohol, they will also be tolerant to the CNS depressants benzodiazepines, even if they have never taken a benzodiazepine before in their life.
What is drug dependence and withdrawl?
Drug dependence and withdrawal is defined as an abnormal physiological state produced by repeated administration of a drug that leads to the appearance of a characteristic and specific group of symptoms (withdrawal syndrome) when drug administration is discontinued or the dose is decreased.
