Health Psychology

Substance Abuse: Heroin

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Heroin —————- Diamorphine Hydrochloride

Heroin is an opiate, which acts as a depressant and analgesic (painkiller) in the central nervous system. It is produced from morphine, which comes from the opium or Asian Poppy.

 

 

Mode of Action:

Heroin acts at the opioid receptor sites in the brain. It changes the action of dopamine in the reward pathway of the brain, releasing more dopamine than usual. Heroin is converted into morphine that works at the opioid receptors at the synapse. The morphine binds to receptors to reduce the inhibitory (preventing) effect of GABA on dopaminergic neurones (those that release dopamine). The result is more dopamine activity and the release of dopamine into the synaptic cleft. If the dopaminergic reward pathway continues to be stimulated, this leads to feelings of euphoria.

                                                               Heroin User

Heroin = more availability of dopamine

Heroin mimics the effects of endorphins (pleasure). It is therefore an agonist.

 

During everyday activity, a moderate amount of endorphin is naturally produced, causing the release of dopamine and facilitates the reward systems in the brain. Heroin acts like a massive release of endorphin in the brain. The heroin floods the endorphin receptors, stimulating the two actions of endorphins. Large quantities of dopamine are released, activating the reward system and producing feelings of well-being.

 

 

Effects:

Short-term Effects:

  • Pleasure
  • Reduction of pain
  • A ‘rush’ (dry mouth, heavy limbs, flushing of the skin, feelings of sickness and severe itching)
  • A sense of relaxation
  • Drowsiness
  • Slowing of breathing and heart rate
  • Pupil constriction
  • Constipation

Long-term Effects:

  • Collapsed veins and infections (through the use of needles)
  • Clogging of blood vessels
  • Difficulty in concentrating
  • Lack of attention
  • Memory problems
  • Increased risk of miscarriage
  • Death (may occur if the user stops breathing)

Tolerance

Tolerance means that, as a drug is taken increasingly over a period of time, more of it is needed to obtain the feelings that were first produced. The same dose of drug will not produce the same feeling of euphoria. Tolerance goes with being physically dependent. It is also linked to addiction.

Studies have shown dosage rates can increase tenfold in three to four months (Griffiths, Bigelow and Heningfield, 1980). Regular uses take heroin at a high enough level to kill a non-user.

Withdrawal:

Even if heroin is taken (in a sustained way) for only three days, withdrawal symptoms can occur when it is stopped.

Immediate symptoms include:

  • Pain
  • Nausea
  • Sweating
  • Diarrhoea
  • Extreme anxiety
  • Depression

Symptoms start 6 – 12 hours after the last fix. These symptoms peak after 26 – 72 hours.

Sources:

  • Russell, J. (2011). Angles on psychology. Haddenham: Folens.
  • Brain, C. (2009). Edexcel A2 psychology. London: Edexcel.
  • Brain, C. (2009). Edexcel A2 psychology. London: Philip Allan.

Substance Abuse: Alcohol

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Alcohol is a depressant drug which affects the nervous system. It is a legal substance, and so is socially-acceptable (in certain circumstances).

Mode of action:

Alcohol serves to make GABA more effective, meaning that it makes it more difficult for messages to be transmitted. It also reduces the effectiveness of the inhibitory mechanisms that ensure we behave in a way that is socially-acceptable and anaesthetises nerve endings at noradrenalin synapses so they become less effective. Noradrenalin synapses trigger the fight-flight mechanism.

Alcohol does not just prevent the improvement of the reflexes that these synapses would bring, it also slows the reflexes because of the increased effectiveness of the GABA system.

 Effects:

Short-Term Effects:

  • Dilated skin blood vessels – users feel warm and flushed
  • Reactions slow down – higher levels of perceptions and speech are affected (linked to increase in GABA)
  • Reduces inhibitions – targets the social control areas of the brain
  • Relaxation
  • Confidence
  • Dehydration

Long-Term Effects:

  • Damage to organs, including heart, liver, pancreas, the brain and the nervous system
  • Increase in blood pressure and cholesterol levels
  • Strokes
  • Cancer (i.e. liver cancer)
  • Depression
  • Liver disease

Tolerance:

Alcohol affects behaviour rapidly, and just a small amount produces measurable effects. However, short-term tolerance also develops quickly, so that, as blood alcohol level drops, the individual feels sober before they actually are.

Alcohol consumption stimulates the body to produce an enzyme that breaks alcohol down more quickly – in just a few weeks, a drinker will need to consume about 50% more alcohol to achieve the same effect.

 

Physical Dependence:

  • Irritability
  • Shaking
  • Inability to restrict intake – may end up drinking until they pass out
  • Sweating
  • Nausea
  • Visual hallucinations

Psychological Dependence:

  • The individual may place drinking above other activities in their life (i.e. personal hygiene)
  • Access to alcohol becomes a ‘coping strategy’
  • Depression
  • Anxiety
  • Insomnia
  • Restlessness
  • Irritability

Withdrawal:

Withdrawal symptoms depend largely on the level of use and addiction. They are influenced by two factors peculiar to alcohol. Firstly, habituation to the level of alcohol is extremely fast both psychologically and physiologically within a drinking bout. Secondly, following a drinking bout, the feeling of sobering occurs much more quickly than the actual physiological process.

Symptoms include:

  • Agitation
  • Uncontrollable shaking
  • Cramp
  • Nausea
  • Sweating
  • Irregular heartbeat
  • Vivid dreaming

Symptoms usually occur 8 – 12 hours after the last drink. These can last up to 48 hours.

Sources:

Evaluation Of Biological Explanations For Substance Abuse

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Strengths:

  • Biological explanations have validity because objective data demonstrate visible activity under certain circumstances. For example, PET scans have shown a difference in neuronal activity when smoking normal and low-nicotine cigarettes.
  • Biological explanations are also supported by animal studies, which have reliability because they are highly controlled and replicable. For example, many animal studies have shown how different drugs affect receptors in different ways.
  • Research in biopsychology is supported by findings in other areas of biology, which reinforces the biological explanation. For example, identification of the mu-opioid gene matches findings about the mu-opioid receptors.

Limitations:

  • Biological explanations may not be reliable if animal studies show differences between animals. For example, different studies show differences in mice when studying different opioid receptors. This means that we should be cautious when generalising from animal studies to explanations of human behaviour.
  • Although the findings of PET scans have some validity, we must remember that the behaviours being measured take place in an artificial environment, so the validity can still be questioned.
  • Generalising the results from animal studies poses issues with validity. Human beings are not the same as animals, therefore the results obtained from these studies may not apply.

Explanations Of Substance Misuse: The Biological Approach

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People are not likely to start taking a recreational drug for a reason other than some form of pleasure – they start using the drug and like the resultant feelings.

A biological explanation may serve to explain why some individuals continue to take the drug, even if at some level they wish to stop. The brain seems to have an agenda of its own when someone who has started taking an addictive drug wants to stop, and this is the biological agenda.

The brain continues to change as a recreational drug is taken in terms of biochemical structure, memory processes and in control over motor skills, until the person is addicted.

Biochemical Explanation for substance misuse:

Drugs are chemicals and they work in the brain to provide a pleasure reaction and, for some drugs, an addiction reaction. Prescribed drugs, such as tranquilisers and anti-schizophrenic drugs, work in the same way. The drugs act like other neurotransmitters – when released by an electrical impulse, the neurotransmitter chooses a synaptic gap to fit with receptors of another neurone. Drugs can also prevent the reuptake of a neurotransmitter, which means the neural transmission is blocked.

Dopamine and serotonin are linked to pleasure and positive emotions. Endorphins increase pleasure and reduce pain. Drugs act in much the same way as these neurotransmitters. They work in three different ways:

  • they fit the receptors of a neuron and stimulate the same response as a similar neurotransmitter (agonist);
  • they fit the receptors of a neuron and block access to the receptor, preventing the transmission of a signal  (antagonist);
  • they prevent the reuptake of neurotransmitters, so they remain at the synapse and are able to attach to the receptors (more availability of that neurotransmitter).

For example, cocaine stimulates the dopamine receptors , increasing the availability of dopamine messages (as there is more dopamine in the synaptic cleft).

 

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Opioids (like heroin) prevent the reuptake of dopamine, extending its availability to post-synaptic receptors. Heroin and alcohol increase endorphin arousal, increasing pleasure and reducing pain.

Pleasure Centre Explanation:

Research by Olds and Milner (1954) suggested that there are pleasure centres in the brain, linked to motivation areas. The researchers experimented with rats and found they would press a lever to get an electrical stimulation to the septal areas of the brain rather than press for food or drink. Rats would even cross a grid where they received painful shocks in order to reach the reward of stimulating these pleasure areas. The electrode the rats achieved was attached to the rat’s hypothalamus, so the pleasure area is thought to be in that area of the brain.

Genetic Vulnerability:

The reason for starting to take a drug may not be biological, but some people may be genetically more responsive to drugs, prone to develop addictive personalities or predisposed to physical dependence. This means that addiction may be more prevalent in those who share a similar gene…

Schinka et al (2002) identified a gene associated with addiction – the mu-opioid gene. Alcoholics were found to lack a form of the gene, when compared with non-alcoholics in the study. Family and twin studies also indicate that there is a genetic basis for risk of drug dependency. Laboratory studies have reinforced this work, and mice without the mu-opioid receptor did not drink alcohol after they had been trained to drink it in other circumstance

Inherited personality traits, such as extraversion or sensation-seeking, may also be linked with addictive behaviour (i.e. gambling).

Sources:

The Biopsychosocial Model of Health

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This models looks at the biological, psychological and social factors that are associated with health and illness.

The Biopsychosocial model does not look for single causes, but starts from the assumption that health and illness has many causes, and also produces many effects.

The Biopsychosocial Model of Health

The Biopsychosocial model looks at three systems: the social system (i.e. family), the psychological system (i.e. behaviour) and the biological system (i.e. organs).

One biological system that has received a lot of attention from psychologists and physicians is the immune system, which is a collection of responses that allow the body to neutralise, eliminate or control the factors that produce disease. It seems possible that there are connections between the immune system and the experience of stress which would fit into an individual’s psychological systems. The experience of stress is also affected by the social systems an individual lives in – for example, their family.

The development of this Biopsychosocial model moves the emphasis away from traditional Western medicine and towards psychology.

Psychological Definitions For Health Psychology

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Substance Misuse – is when a drug – defined as a mind-altering substance – is used in such a way that the individual’s physical and mental health is affected.

Synapse – a gap between two neurons where information can be passed from one to another.

Tolerance – where a drug user becomes used to a particular level of drug so that more and more is required to maintain the effect.

Physical Dependence – when the brain can no longer function normally without a drug supplementing the neurotransmitter level.

Psychological Dependence – a compulsion to take a drug for the pleasant effects it has, such as feeling of exhilaration or self-confidence. It may lead to misuse. This does not produce withdrawal effects.

Withdrawal – when an individual refrains from taking a drug (after becoming physically-dependent), they experience symptoms.

How Neurotransmitters Are Passed From One Neuron To Another

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Communication between two neurons begins when an electrical impulse, called an action potential, travels along the axon of a presynaptic neuron towards the axon terminal. Neurotransmitters drift across the synaptic space and bind to receptors on the post-synaptic neuron. The binding of the neurotransmitter to its receptor can trigger an action potential in the post-synaptic neuron. Now that the neurotransmitter has relayed its message, it releases from the receptor into the synaptic space. Some of the neurotransmitters degrade, while others are carried back into the synaptic space (re-uptake).

Neurotransmitters passing from one neuron to the other

https://www.youtube.com/watch?v=p5zFgT4aofA

The Work Of The Health Psychologist

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Health psychologists work with health professionals, such as doctors, dentists, occupational therapists and dieticians. They may carry out clinical work themselves (e.g. counselling), ore may undertake research. They are often involved in health promotion campaigns and their role is as much about prevention as cure.

When carrying out research, health psychologists use methods, such as experiments, longitudinal studies, cross-sectional studies, and case studies.

Health Psychologists deal with:

  • Disease (such as heart problems)
  • Substance misuse
  • Social support
  • Emotional state

Did You Know?

The word ‘health’ comes from an Anglo-Saxon term meaning ‘wholeness’.

Types of Neurotransmitters

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Monoamine Neurotransmitters:

DOPAMINE: ——— > Pleasure

Insufficient dopamine produces the symptoms of Parkinson’s disease, while an excess amount of dopamine is associated with paranoia. It is one of the neurotransmitters related to ‘feeling good’ as a pulse of activity through the dopamine system in the brain is linked to feeling happy, even euphoric. This is called the reward system.

NORADRENALIN: ——-> ‘Fight or Flight’ Mechanism

Noradrenalin in the bloodstream is linked with adrenalin in the fight-flight mechanism. It is also found in the brain as a neurotransmitter where it boosts attention and one’s ability to focus and is also linked to mood.

SEROTONIN ——-> Emotions

This is closely linked to emotions and there is evidence that an incorrect level can make one feel depressed, angry or aggressive.

Other neurotransmitters:

ENDORPHINS

The body’s natural opiates, they have two different effects:

– They are inhibitory neurotransmitters, occupying and therefore blocking receptor sites for pain.

– Make one feel good through the stimulation of the dopamine reward system.

GABA: ——> slows everything down

This is the most important inhibitory neurotransmitter. It makes it more difficult for messages to be transmitted from one synapse to another. It slows neural activity, so is referred to as a depressant.