Drug Dependence Flashcards
(56 cards)
How many of the adult British population have taken illegal drugs?
One in three
What is addiction?
Chronic disease characterised by drug seeking and use that is compulsive, or difficult to control, despite harmful consequences.
Define drug abuse.
A pattern of drug use in which the users consume the substance in amounts or using methods which are directly or indirectly harmful to themselves or others.
Define drug dependence.
An adaptive state that develops after repeated drug use and which results in withdrawal symptoms upon cessation of drug use.
Define drug tolerance.
The diminishing effect of a drug which results after repeated administration at a set dose.
Define psychological dependence.
Dependence that involves emotional–motivational withdrawal symptoms (e.g. dysphoria, depression, anhedonia, restlessness).
Define physical dependence.
Dependence that involves significant physical–somatic withdrawal symptoms (e.g. fatigue, nausea, seizures, pain, delirium tremens).
Classification of drugs under the Misuse of Drugs Act 1971 - give examples for class A, B and C.
Class A: heroin, methadone, cocaine, crack cocaine, ecstasy, LSD, magic mushrooms, methadone…
Class B: amphetamines, barbiturates, ketamine, methylphenidate, codeine, cannabis…
Class C: anabolic steroids, benzodiazepines, gamma hydroxybutyrate, gamma butyrolactone, khat…
What are the receptors for…
Opiates?
Cocaine?
Amphetamine?
Mu and delta opioid receptors - agonist
DA, NAd and 5-HT uptake systems - antagonist
Monoaminergic transmission:uptake systems - agonist of TAAR1
What are the receptors for…
Ethanol?
Nicotine?
Cannabinoids?
GABA A and NMDA receptors - modulator
Nicotinic receptors - agonist
CB1 receptors - agonist
What are the receptors for…
Ketamine and phencyclidine?
Hallucinogens?
Barbiturates and benzodiazepines?
NMDA glutamate receptors - antagonist
5-HT 2A receptors - agonist
GABA A receptors - agonist
What neurotransmitter is particularly important in pleasure?
Dopamine - occupancy of dopamine receptors by labelled marker decreases when the stimulant induces pleasure, as it is displaced by dopamine.
The dopaminergic projection from _____ to _____ is essential in drug dependence.
Ventral tegmental area
Nucleus accumbens
What are the four stages of the addiction cycle?
- Intoxication – positive reinforcement. Impaired self-awareness.
- Bingeing - loss of control.
- Withdrawal/negative affect - negative reinforcement. Amotivation and anhedonia.
- Craving – conditioned positive and negative reinforcement. Drug expectation and attention bias.
Mechanisms underlying withdrawal.
Activation of kappa opioid receptors (endogenous receptor for dynorphin-like peptides) can trigger dysphoria, by reducing dopamine release. Administration of drugs of abuse increases the release of dopamine. Chronic intake leads to up-regulation of dynorphin, which might inhibit drug-induced dopamine release. After stopping the drug, these adaptations remain unopposed which contributes to the negative emotional state associated with drug withdrawal.
Brain areas involved in the development of drug dependence. (6)
Ventral tegmental area Nucleus accumbens (one of first to be involved) Insula Hippocampus Prefrontal cortex Amygdala (last to be involved)
Brain connectivity changes occurs during the development of addiction. There is gradual involvement of many CNS structures. There is increasing ________ with increasing use of drugs, and increasing ______/________.
Neuroplasticity
Compulsivity/loss of control
In addicts what can be said about the availability of dopamine D2 receptors and cerebral metabolism?
In what brain area is this particularly prevalent?
Reduced - these have a linear relationship, they increase/decrease with each other.
Orbitofrontal cortex and cingulate gyrus
In addicts, there are processes that are impaired. These include:
Self-control, emotional regulation, motivation, attention, memory, decision making, insight and salience attribution.
What area of the brain is this associated with?
Prefrontal cortex
Addicts show iRISA. What does this stand for?
Impaired response inhibition and salience attribution
Chronic drug abuse affects gene regulation. How?
Gradual accumulation in gene expression changes.
Which opiates and psychostimulants can particularly effect neuronal structure? What effect do they have?
Cocaine and morphine
Morphine decreases the total dendritic length and dendritic spine density. Cocaine increases it.
What classifies as hazardous drinking?
Regular consumption of over 5 units a day for men and over 3 units a day for women.
What does acute alcohol intoxication cause?
Euphoria followed by depressed mood, slurring of speech, ataxia, general incoordination, and pupillary dilatation.
