The effect of recreational drugs on the transmission process in the CNS Flashcards
Define “recreational drugs”.
Drugs taken without medical justification for their psychoactive effects, in the belief that occasional use is not habit-forming or addictive
Define “drug addiction”.
The positive responses of the reward system in the brain causing an individual to be reliant on a drug for normal functioning
Define the “Dopamine Reward Pathway”.
The structures and neurones in the brain associated with the neurotransmitter dopamine to cause feelings of reward
Define “desensitisation”.
Requiring a higher concentration or dosage of a drug to cause the same feeling due to a loss of response at the synaptic level
What is the biological explanation for drug addiction? (5 points)
Recreational drugs often activate the limbic system of the brain
It consists of the hypothalamus, hippocampus and amygdala - involved in regulating arousal, emotions and mood
Stimulation of the Dopamine reward pathway as part of the limbic system causes people to associate positive emotions with drug-taking
This can then lead to desensitisation at the synaptic level
In extreme cases, overuse of recreational drugs can lead to addiction
What is the biological explanation for the emotions experienced when on drugs? (2 points)
Stimulants like cocaine cause amplified signaling at the synaptic level, leading to euphoric emotions and the feeling of a ‘high’
When a person takes recreational drugs they are likely to feel euphoric emotions followed by dysphoria, a period of anxiety or dissatisfaction
What are the 4 drugs you have to know about for Edexcel A-Level Psychology?
Nicotine
Cocaine
Alcohol
Cannabis
What is nicotine and how does it affect synaptic transmission? (4 points)
Psychoactive component of tobacco
Acts as an agonist of nicotinic acetylcholine receptors
Binds to them and initiates an action potential, increasing neurotransmission
Its rewarding and addictive abilities link to increased dopamine release in the nucleus accumbens reward pathway of the brain
What is cocaine and how does it affect synaptic transmission? (2 points)
Strong recreational stimulant drug
Increases energy, alertness, euphoria and heart rate
How does cocaine affect synaptic transmission? (3 steps)
- Blocks reuptake protein pumps which normally remove monoamine neurotransmitters from the synapse
- Causes an increase in monoamine neurotransmitters like dopamine and serotonin in the synapse
- Leads to continual depolarisation and stimulation of action potentials
How does alcohol affect synaptic transmission? (3 points)
Temporarily boosts serotonin levels - makes people feel happier
Increases the inhibitory action of GABA in the long-term - post-synaptic neurone hyperpolarises
Action potentials and neuronal transmission decreased - slows down reactions
What is GABA? (2 points)
An inhibitory neurotransmitter that reduces action potentials
Does this by causing hyperpolarisation in the post-synaptic membrane with the influx of Cl-ions
How does cannabis affect synaptic transmission? (4 points)
THC binds to CB1 cannabinoid receptors - is a partial agonist of CB1 receptors in the:
Cerebral cortex - causes cognitive effects
Cerebellum - causes sedative effects
Brainstem - causes analgesic (pain relief) effects
What is THC? (2 points)
Active ingredient found in marijuana
Causes euphoria, sedation and impaired cognitive function
What are the 4 types of effects of THC depending on dosage?
Small doses - sedates
Moderate doses - stimulates
Large doses - acts as a hallucinogen
Very large doses - may cause psychotic-like symptoms
What are the 5 evaluation points for the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation?
Supporting:
Strengths - Benowitz (2009) & Varenicline
Application - Manzanares (2006)
Refuting:
Credibility - Lewis et al (2020) and Allen & Stevens (1994)
Other explanations - Genetics
Debates - Freud
What is Varenicline? (2 points)
A synthetic smoking cessation tablet and partial agonist at nicotinic receptors
Causing dopamine release to create the same positive reinforcement felt when smoking tobacco
How is Benowitz (2009) a strength of the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation? (3 points)
Found that nicotine binds to nicotinic receptors in the brain to facilitate neurotransmitter release
Has led to the development of new treatment options for tobacco addiction including nicotine replacement therapy
The neurobiological explanation of recreational drugs can be used for the benefit of human understanding
How does Lewis et al (2020) refute the credibility of the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation? (3 points)
Lack of generalisability despite empirical research demonstrating a link between cocaine and D2 dopamine receptors
Lewis et al (2020) found that cocaine causes elevated dopamine levels and inhibition of striatal acetylcholine signalling in male mice
Difficult to generalise findings from animal models to human behaviour - rats possess simpler CNS and brain anatomy than humans
How does Allen & Stevens (1994) refute the credibility of the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation? (3 points)
Found that over 50% of presynaptic nerve impulses failed to evoke a postsynaptic response in a hippocampal cell slice
This was due to conduction failures - questionable reliability
Empirical research studies of recreational drugs and neurotransmission are not entirely falsifiable - reduced credibility
How is genetics an alternate explanation for the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation? (2 points)
Cloninger’s (1970) studies of MZ twins showed that if one twin had an addiction, the other twin was likely to also have an addiction
Further twin studies have consistently found that MZ twins are more likely to both have an addiction than DZ twins
Is there room for debate on the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation? (3 points)
Neurobiological explanations remain biologically reductionist - they fail to account for individual differences, including:
+ Personality
+ Free will to choose
+ Learning how to use recreational drugs in the environment
Freud suggests that recreational drug use is driven by a desire to escape from past traumatic experiences and to seek pleasure - can become a source of addiction
How does Manzanares (2006) support the implications of recreational drugs on synaptic neurotransmission as a neurobiological explanation being applicable to real life? (3 points)
Demonstrated the role of THC and cannabinoid receptor agonists in alleviating acute and chronic pain episodes
Despite high doses of cannabis causing hallucinogenic effects, preclinical and clinical studies have suggested lower doses may be useful in treating diseases involving acute or chronic pain
Neurobiological explanations have important applications for society as medicinal treatments
