8.1.2 biological causes of drug taking

Question 1

What is the mode of action for alcohol

Answer 1

alcohol makes GABA more effective by further slowing down the speed that messages are passed across synapses.

Alcohol is an agonist of GABA receptors. A glutamate antagonist (excitatory neurotransmitter ) .

Alcohol increases the amount of dopamine and serotonin.

Stimulates the reward pathway. Fight or flight reflexes slow down, noradrenaline action reduced. frontal lobe affected, inhibitory systems are less effective and more likely to take risks.

Reduces serotonin activity long-term and creates depression

Question 2

What are the physical effects of taking alcohol

Answer 2

blood vessels dilate, become warm and flushed. GABA made more effective and speech affected, slower reaction times. Frontal lobes depressed, motor skills and coordination affected.

Dehydration caused by inhibition of ADH which leads to increased urination

Question 3

What are the psychological effects of taking alcohol

Answer 3

Targets social areas of brain. reduces stress levels and can lead to psychological dependence. Reduces effectiveness of inhibitory mechanisms. Leads to increased confidence and relaxation but then can lead to exhibitionism and extreme behaviour

Question 4

What is the tolerance of someone taking alcohol

Answer 4

Short-term tolerance can develop quickly.

Body produces more enzymes to break down alcohol quickly and more alcohol is needed to produce the same affect

Question 5

describe Withdrawal of alcohol

Answer 5

6 to 12 hours after the last drink is the hangover.

Shakes, vomiting, nausea, headaches.

Heavy drinkers can experience alcohol withdrawal symptoms. Brain becomes hyper excited. Firefly actions may become overactive leading to hallucinations, confusion, anxiety and can be fatal

Question 6

What is the mode of action for heroin

Answer 6

attaches to receptors for endorphins (Mu opioid receptors). endorphins cause the release of dopamine in the reward pathway.

Endorphins have an analgesic effect (released naturally during stress and pain situations) . heroin taken and enters the brain, is hydrolysed morphine, morphine binds to opioid receptors in the reward pathway.

This activates opioid receptors to inhibit activation of GABA, Low GABA means dopamine floods the synapse.

Sustained activation of postsynaptic membrane and pleasurable feelings experienced

Question 7

What are the physical effects of heroin

Answer 7

Warm skin, dry mouth, heavy limbs.

Nausea/vomiting.

Heart rate and breathing rate reduced, affects the activity of brain stem. Mental functioning impaired

Question 8

What are the psychological effects of taking heroin

Answer 8

euphoria. Anal gestic affects. Removes aches and pains and gives calm feelings.

We’re not taking heroin, the user compares their life to no feelings of euphoria and they can become confused and anxious so want to take more heroin to reduce this

Question 9

Describe tolerance of heroin

Answer 9

produces long-term chemical imbalances. Which are not easily reversed.

The brain activates less of its own natural production of dopamine.

In order to get the same high uses need to increase dosage.

Certain parts of the brain will only function in presence of the drug

Question 10

Describe withdrawal of heroin

Answer 10

Agitation, muscle and bone pain, insomnia and cold flushes

Question 11

Describe mode of action for nicotine

Answer 11

enters brain and binds to nicotinic receptors, stimulating the release of ACh.

Same molecular shape as neurotransmitter so works as an agonist stimulating the synapses.

The synapse has become flooded with ACh.

Noradrenaline levels rise and the sympathetic nervous system is stimulated. Increases transmission of dopamine , positive feelings towards smoking.

Endorphin levels rise and pleasure and relaxation felt

Question 12

Describe physical effects of nicotine

Answer 12

highly addictive. Instantaneous effect.

Effects were off after a few minutes causing the need to smoke repeatedly.

Stimulates dopamine reward system.

Increases alertness.

Increases carbon dioxide in the blood.

Less oxygen available, grey skin, irregular heartbeat, premature skin aging and lung disorders

Question 13

What are the psychological effects of nicotine

Answer 13

Relaxation, stimulates reward system, reduces stress

Question 14

Describe the tolerance of nicotine

Answer 14

Brain creates more nicotinic receptors. Metabolise quickly. Tolerance lasts overnight, therefore first cigarette is the strongest.

Person smokes more frequently to avoid withdrawal symptoms

Question 15

Describe withdrawal of nicotine

Answer 15

irritability, sleep disturbance, headaches, difficulty concentrating, increased appetite. Psychological difficulties of not having the enjoyable act of smoking

Question 16

evaluate the biological explanation of drug taking

Answer 16

intro : drugs are chemicals that have an effect on humans including cocaine and heroin. They are called recreational because they are taking for pleasure (specifically psychoactive substances) and can alter the sense of consciousness. People who take drugs, can easily become addicted due to the psychological and physiological dependency and the biological explanation explores this further

STRENGTH: On the one hand the biological explanation of drugtaking is reliable and valid as animal studies have shown biological changes in the brain due to drug misuse, support in the bio chemical theory.Also it has been found that neurological activity in the brain of addicts have also been shown to be different to non-addicts, supporting the biological explanation. This therefore illustrates that the biological explanation is clearly supported by studies on both animals and humans and therefore is reliable

WEAKNESS: however despite this, the biological explanation is not quite yet fully developed and therefore is quite reductionist as it fails to consider the other explanations like social/learning. for Example the biological approach ignores the role of nurture, and that addiction can be explained by social learning for example being in the same friendship group is drug takers, reinforcement and as previously stated peer pressure. Moreover many people try and infrequently use drugs like alcohol and don’t become addicted, suggesting that individual differences play a key role in addiction and drug taking, and therefore accentuates that the biological explanation for drugtaking is not yet fully developed and is reductionist

STRENGTH: however another positive of the biological explanation for drugtaking is that it is clearly supported by further case studies like Alda Milner in 1954, who found the reward pathway. In particular they found a pleasure centre in the brain of rats and this pleasure centre is also a key idea in the biological explanation for drugtaking. For examples when a person takes a drug like alcohol, it increases the amount of dopamine and serotonin, so the person then has a dependency on the drug for that feeling of happiness and associates the drug with it

CONC: therefore, on balance, it is clear that the biological explanation for drugtaking is supported by many studies on both humans and animals, however is quite reductionist as doesn’t take into account individual differences or other explanations to further research is needed to develop the biological explanation