3.1.2 - Drugs

Question 1

Effects of drugs on transmission process:

AO1 x 4

Answer 1

• drugs are chemicals that have an effect on the CNS they are called psychoactive drugs because they alter brain function which changes our mood, perception or conscious experience
• drugs act by changing the way neurotransmitters operate. Most psychoactive drugs work on the dopamine system increasing the amount in the reward pathway = euphoric, pleasant feeling this that encourages the repetition of behavior which leads to drug addiction
• the brain reacts to the sudden increase in dopamine and reduces its own natural production so once the drug has worn off the person has less dopamine than they would for normal brain functioning.
• This causes an unpleasurable experience and motivates a person to take more drugs to reproduce the high which can cause further reduction of dopamine which makes the person physically dependent on the drug to avoid withdrawal

Question 2

Example Drug: Cannabis

AO1 x 4

Answer 2

• cannabis acts by binding onto cannabinoid receptors; One type is found in many regions of the brain and the other type in the immune system
• There are many cannabinoid receptors in the hippocampus and taking cannabis can therefore affect memory function
• Cannabis binds to the cannabinoid receptors, effectively blocking them which means less activity in the neurons
• However, in the rewards system more dopamine is released as happens with other drugs and it is this excess of dopamine in the reward system that gives the high

Question 3

AO3: Evaluations (Drug research)

Strengths x 2

Answer 3

• One strength is that the observation of people who takerecreationaldrugs gives drug research more credibility. Researchhasfound thatatfirst users experience great pleasure but thencanbecome addicted and need more drugs to experience the same affect. Therefore, supporting that drugs causes a person to produce less dopamine than they would have for normal brain functioning which is what motivates addiction as they crave the same pleasurable experience.
• Another strength is that research brain scanning,such as PET scans, has been increasingly used which increases scientific credibility as more than one person can look at the scans to check the results. Therefore, investigations can be done in controlled environmentsto show that the use ofdrugs, such as heroin, is the cause of changesto neurotransmitter levels with resulting effects onbehaviour.

Question 4

AO3: Evaluations (Drug research)

Weaknesses x 2

Answer 4

• One weakness is that, for example Allen and Stevens found that synaptic transmission regarding hippocampal neurons was very unreliable, with less than half the neurotransmitters arriving from the presynaptic neuron being picked up by the postsynaptic neuron. Therefore there may be many factors at work in the synoptic transmission that could influence how drugs impact behaviour.
• Another weakness is that most synaptic transmission evidence has come from animal studies where lesions can be made. Therefore results may not be transferable and generalizable to human behaviour as human brains have more emotional function. Therefore brains are different so drugs may impact animals behaviour differently to humans