Substance use and addiction Flashcards
Single Convention on Narcotic Drugs of 1961
- Limit possession, use, trade in, distribution, import, export, manufacture and production of drugs to
medical and scientific purposes. - Combat drug trafficking through international cooperation to deter and discourage drug traffickers
Convention on Psychotropic Substances 1971
- Responded to the diversification and expansion of the spectrum of drugs (Turn on, tune in, drop out);
- Introduced controls over synthetic drugs and their therapeutic values.
Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances
1988
- Really aimed at traffickers;
- Provides international cooperation through extradition, controlled deliveries, transfer of proceedings, etc
In Canada, all seized drugs are sent to Health
Canada for analysis by the
Drug Analysis
Service (DAS)
defining controlled substances Schedule I
- No accepted medical use;
- Lack of accepted safety for use under medical supervision;
- High potential for “abuse”;
- Heroin, MDMA. (Note: Cannabis was here)
defining controlled substances Schedule 2
- High potential for “abuse” which may lead to severe psychological
and/or physical dependence; - Opiates: methadone, (Dolophine®, oxycodone (OxyContin®,
Percocet®), fentanyl (Sublimaze®, Duragesic®), morphine,
opium, codeine. - Stimulants: amphetamine (Dexedrine®, Adderall®),
methamphetamine (Desoxyn®), and methylphenidate (Ritalin®
defining controlled substances Schedule 3
- Less potential for ”abuse” than Schedules I or II and use may lead to
moderate or low physical dependence or high psychological
dependence; - Examples: products with <15mg of hydrocodone (Vicodin®),
products containing <90mg of codeine (Tylenol with Codeine®),
buprenorphine (Suboxone®), ketamine and anabolic steroids
defining controlled substances schedule 4
- Low potential for abuse relative to substances in Schedule III
- Examples: alprazolam (Xanax®), clonazepam (Klonopin®),
diazepam (Valium®), lorazepam (Ativan®), midazolam (Versed®)
and triazolam (Halcion®
defining controlled substances schedule 5
- Low potential for abuse relative to substances listed
in Schedule IV and consist primarily of preparations
containing limited quantities of certain opiates - Examples: cough preparations containing <200mg of
codeine per 100mL or 100g - Examples: Robitussin AC®, Phenegan with Codein®
and ezogabine.
substances that result in euphoria act as positive
reinforcers and can lead to
addiction
two major things that makes a substance addictive
euphoric effects and withdrawal symptoms
According to Koob & Volkow (2010), addiction
involves a cycle composed of three stages:
- Binge intoxication – characterized by
impulsivity; - Withdrawal/negative affect – characterized by
the transition from impulsivity to compulsivity; - Preoccupation/anticipation – characterized by
both impulsivity & compulsivity.
The shift from impulsivity to compulsivity coincides
with a shift from
positive reinforcement to
negative reinforcement
Olds & Milner, 1954 Discovered
(by accident) neural circuits responsible for biological basis of pleasure in the limbic system;
- Gradually, the anatomical pathways and neurochemical
substances were determined and mapped.
Most, if not all, drugs prone to
dependence/addiction share a common
denominator:
the dopaminergic system
plays a central role in reward and
reinforcement
the mesolimbic and
mesocortical dopaminergic pathways mediate:
These pathways mediate the rewarding
and reinforcing effects of natural
rewards (and drugs)
The .. is responsible for
pleasure/euphoria and is critical to the development of addiction.
Nucleus Accumbens (NAc or NAcc)
Major NAc inputs:
- Prefrontal association cortices;
- Basolateral amygdala;
- Ventral Tegmental Area (VTA, A10);
- CA1 region of hippocampus (remember LTP!)
Major NAc outputs:
- Basal ganglia, ventral globus pallidus (impulsivity!);
- VTA, Substantia Nigra, Reticular Formation;
NAc is subdivided into two anatomically and functionally distinct regions:
- Shell
- Receives input from BLA and ventral subiculum (major
output from hippocampus);
- Considered “extended amygdala”; - Core
- Inputs from BLA and parahippocampal regions
The… is a large collection of
ascending and descending
pathways
Medial Forebrain Bundle
(MFB)
The … is also very important for the pleasure/reward associated with drug use, as it
mediates the emotional characteristics of drug use
amygdala
The ….. records memories of
experiences with drug use. Heavily involved in conditioned place preference, anticipation of drug use, and relapse
hippocampus
Withdrawal from drugs typically elicits symptoms
characterized by:
irritability, anxiety and depression
The neuroadaptations can be divided into two
progressive processes
- Within-system adaptation;
- Between-systems adaptation
Within-System Adaptions:
- Direct attempt by the brain to counteract the repeated drug-
induced activation of that circuit; - Cells will start pulling receptors from the membrane,
releasing retroactive transmitters to slow neurotransmitter
release, etc
Between Systems Adaptations:
- Gradual recruitment of the anti-reward system;
- Neuroanatomical make up of the anti-reward system is the
extended amygdala (i.e. bed nucleus of the stria terminalis,
central nucleus of the amygdala, nucleus accumbens shell) - Norepinephrine, corticotropin-releasing factor (CRF) and
dynorphin are the main transmitters involved in this system; - Naturally, this system is in place to inhibit the reward system
and mediate aversive effects of stress
Opponent Process Model:
- Any stimulus that provokes a
strong affective reaction
(pleasure or discomfort),
automatically sets in motion
an opposing affective
response that is experienced
after the initial stimulus
ends. - Allostatic changes gradually
shift the hedonic setpoint.
The preoccupation/anticipation stage of addiction
involves …. of the prefrontal cortex
dysregulation
