PHARM Module 2 – Drug misuse and Addiction
SECTION 1 – Substance use disorder
Introduction to the opioid crisis and substance use disorder:
- From Jan 2016 to Sept 2020, 19,355CADs died of apparent opioid overdose
o 94% accidental
what is substance use disorder (SUD)?
- Clinically diagnosed by a number of criteria. Once an individual meets a minimum of two
of the criteria, they are classified as having a mild SUD. The more criteria an individual
meets, the more severe the SUD. The various criteria can be generalized into sub
groups:
Social impairments:
- Individual fails to fulfill major roles (school, work) and/or has persistent social or
interpersonal problems. Additionally, social, occupational, or recreational activities may
be given up or reduced.
Risky use:
- The individual may use the substance in physically hazardous situations or use the
substance despite physiological or psychological problems caused by the use.
Impaired control:
- The individual may have persistent craving for the substance (i.e. addiction)
Withdrawal:
- The individual may experience a withdrawal syndrome after stopping use of the
substance
Tolerance:
- The individual may develop tolerance to the substance
Addiction
- The impaired control associated with SUD manifests as emotional and mental
preoccupation with the drug’s effects and by a persistent craving for the drug,
regardless of the consequences.
The dopamine hypothesis
Effect on reward systems:
- Commonly misused drugs increase dopamine in the reward systems of the brain (i.e.
limbic system)
- Other neurotransmitter systems are involved in substance misuse, but the increase in
dopamine appears to be a key component of the brain’s reward system.
Dopamine increase:
- These dopaminergic systems are also responsible for natural rewards such as food and
sex, as well as for stimulus-related rewards such as video games and gambling
,Characteristics of addictive drugs
Increase dopamine
- central nervous system stimulants:
o cocaine
o amphetamines
o nicotine
o caffeine
- opioids
o morphine
o heroin
o oxycotin
- and other drugs like alcohol and cannabis
Produce novelty
- Lysergic acid diethylamide (LSD)
- Ecstasy, also known as MDMA
Reduce anxiety
- CNS depressants:
o Benzodiazepines
o Barbiturates
Drug withdrawal
- An abnormal psychological state produced by repeated administration of a drug that
leads to the appearance of a withdrawal syndrome when drug administration is
discontinued or the dose is decreased
- Severity of withdrawal increases with the speed of drug withdrawal, as the biological
processes that have accommodated to the presence of the drug do not have time to
reverse themselves
- Fear of withdrawal is one factor that contributes to the continuing of drug behaviour
Drugs and their withdrawal symptoms
Stimulants
Two common stimulants are cocaine and amphetamines. Their withdrawal symptoms:
- Sleepiness
- Muscle pain
- Anxiety
- Tremors
- Low mood
- Suicidal ideations (sometimes)
- CVD (sometimes)
Opioids
Common drugs are heroin, morphine and prescription drugs like oxycodone. Their withdrawal
symptoms:
- Sweating
, - Muscle aches
- Agitation
- Diarrhea
- Abdominal cramping
- Vomiting
Drug tolerance
- Repeated administration of a given dose of a drug has progressively less
pharmacological effect, or 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
- Usually expressed as a shortened duration of action and a decreased magnitude of
effect
- The extent and rate of development of tolerance is specific for each drug
- Drug tolerance is reversible upon drug discontinuation
Cross tolerance
- 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. This is displayed in the dose response
curve.
- E.g. if a person is tolerant to the CNS depressant alcohol, they will also be tolerant to the
CNS depressant benzodiazepines, even if they have never taken a benzo before in their
life.
Factors influencing SUD
Certain environments can increase the likelihood of drug misuse and SUD:
Genetic factors
- Can predispose you to an SUD
Pre-existing disorders
- Those with major affective disorder (depression, BPD), anxiety or schizophrenia are at
higher risk for SUD than the general population
Environmental factors
- Exposure to environments that promote drug use, family dynamics, trauma, and
social/work groups
- Spouses and siblings of those with SUD are at a higher risk of developing SUD
Developmental factors
- More vulnerable during certain developmental timeframes
o Adolescence and early adulthood
Stigma of SUD
- People with SUDs have been stigmatized by medical professionals and society
- This can lead to low self-esteem and isolation, a consequence of this is individuals not
receiving the medical or social help that they need.
SECTION 1 – Substance use disorder
Introduction to the opioid crisis and substance use disorder:
- From Jan 2016 to Sept 2020, 19,355CADs died of apparent opioid overdose
o 94% accidental
what is substance use disorder (SUD)?
- Clinically diagnosed by a number of criteria. Once an individual meets a minimum of two
of the criteria, they are classified as having a mild SUD. The more criteria an individual
meets, the more severe the SUD. The various criteria can be generalized into sub
groups:
Social impairments:
- Individual fails to fulfill major roles (school, work) and/or has persistent social or
interpersonal problems. Additionally, social, occupational, or recreational activities may
be given up or reduced.
Risky use:
- The individual may use the substance in physically hazardous situations or use the
substance despite physiological or psychological problems caused by the use.
Impaired control:
- The individual may have persistent craving for the substance (i.e. addiction)
Withdrawal:
- The individual may experience a withdrawal syndrome after stopping use of the
substance
Tolerance:
- The individual may develop tolerance to the substance
Addiction
- The impaired control associated with SUD manifests as emotional and mental
preoccupation with the drug’s effects and by a persistent craving for the drug,
regardless of the consequences.
The dopamine hypothesis
Effect on reward systems:
- Commonly misused drugs increase dopamine in the reward systems of the brain (i.e.
limbic system)
- Other neurotransmitter systems are involved in substance misuse, but the increase in
dopamine appears to be a key component of the brain’s reward system.
Dopamine increase:
- These dopaminergic systems are also responsible for natural rewards such as food and
sex, as well as for stimulus-related rewards such as video games and gambling
,Characteristics of addictive drugs
Increase dopamine
- central nervous system stimulants:
o cocaine
o amphetamines
o nicotine
o caffeine
- opioids
o morphine
o heroin
o oxycotin
- and other drugs like alcohol and cannabis
Produce novelty
- Lysergic acid diethylamide (LSD)
- Ecstasy, also known as MDMA
Reduce anxiety
- CNS depressants:
o Benzodiazepines
o Barbiturates
Drug withdrawal
- An abnormal psychological state produced by repeated administration of a drug that
leads to the appearance of a withdrawal syndrome when drug administration is
discontinued or the dose is decreased
- Severity of withdrawal increases with the speed of drug withdrawal, as the biological
processes that have accommodated to the presence of the drug do not have time to
reverse themselves
- Fear of withdrawal is one factor that contributes to the continuing of drug behaviour
Drugs and their withdrawal symptoms
Stimulants
Two common stimulants are cocaine and amphetamines. Their withdrawal symptoms:
- Sleepiness
- Muscle pain
- Anxiety
- Tremors
- Low mood
- Suicidal ideations (sometimes)
- CVD (sometimes)
Opioids
Common drugs are heroin, morphine and prescription drugs like oxycodone. Their withdrawal
symptoms:
- Sweating
, - Muscle aches
- Agitation
- Diarrhea
- Abdominal cramping
- Vomiting
Drug tolerance
- Repeated administration of a given dose of a drug has progressively less
pharmacological effect, or 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
- Usually expressed as a shortened duration of action and a decreased magnitude of
effect
- The extent and rate of development of tolerance is specific for each drug
- Drug tolerance is reversible upon drug discontinuation
Cross tolerance
- 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. This is displayed in the dose response
curve.
- E.g. if a person is tolerant to the CNS depressant alcohol, they will also be tolerant to the
CNS depressant benzodiazepines, even if they have never taken a benzo before in their
life.
Factors influencing SUD
Certain environments can increase the likelihood of drug misuse and SUD:
Genetic factors
- Can predispose you to an SUD
Pre-existing disorders
- Those with major affective disorder (depression, BPD), anxiety or schizophrenia are at
higher risk for SUD than the general population
Environmental factors
- Exposure to environments that promote drug use, family dynamics, trauma, and
social/work groups
- Spouses and siblings of those with SUD are at a higher risk of developing SUD
Developmental factors
- More vulnerable during certain developmental timeframes
o Adolescence and early adulthood
Stigma of SUD
- People with SUDs have been stigmatized by medical professionals and society
- This can lead to low self-esteem and isolation, a consequence of this is individuals not
receiving the medical or social help that they need.
