A level Psychology exam revision resources written by A level Examiners


Psychology is about explaining behaviour, both normal and abnormal and within psychology there are various approaches, or ways of looking at behaviour, the four most commonly used are;

  • biological
  • psychodynamic
  • behavioural and
  • cognitive approaches

The biological approach is always defined by itself to a degree separate from psychology and then all other approaches come under the title of psychological approaches. All four will be shown here in explaining abnormal behaviour, as determined in the first section of this article, the definitions of abnormality.

The biological approach, is sometimes also referred to as the medical model.

Until the late 18th century mental illness was thought to be linked to the presence of demonic influence, in other words people with abnormal behaviour were thought to be possessed and so the first form of surgery used was trepanning, which consisted of boring holes in the skull to release the demons and evil spirits. Other treatments included exorcism, where a priest or holy man would perform a service to get rid of evil from the person's body. Thankfully the understanding of mental illness evolved late into the 18th century, when Phillipe Pinel developed a classification system for mental illness, comparable to physical illness. The first comprehensive system to classify mental illness was developed by Emil Kraeplin in 1896.

The medical model or biological model is taken from Kraeplin's original medical view of mental illness and is the basis of knowledge for all medically trained psychiatrists. This approach helped reduce stigma, but it also slowed down a broader understanding of mental disorder, in other words it limited the development of psychological, social and environmental explanations, until Freud's theories, which set the ball rolling in these directions.

The biological model assumes abnormal behaviour results from some kind of physical problem. It is concerned with the physiology, disease and genetic factors of mental illness

These physical causes come from one or more of four key areas, which are;

  • micro-organisms
  • genetics
  • bio-chemistry
  • neuro-anatomy

This approach suggests that mental disorder is due to a malfunction in one or more of these areas. The main advantage to this approach, is that if there is a physical malfunction, then there is always a possible cure, by righting that malfunction in some way and therefore any treatment for mental disorder will involve a biological intervention, such as drugs to bring bio-chemistry back into balance.


Micro-organisms are such things as bacteria and viruses. This category also encompasses anything that is not covered in the other three descriptions of why psychopathology is caused.

An example of micro-organisms, is that of General Paresis, (Rosenhan & Seligman 1989) - found that syphilis was rampant in the 16th century, causing delusions of grandeur, progressive forgetfulness, dullness and mental deterioration, late paralysis and death, therefore demonstrating micro-organisms cause mental illness.

As a result of syphilis being identified as the cause of the psychotic behaviour described above, Richard von Krafft-Ebing did a critical experiment looking at syphilis sores and from that study found a way of preventing the disease by injection in 1909. As a result of this injection, syphilis was prevented and therefore the incidence of psychotic behaviour was eradicated.

Another micro-organism (influenza type A) has been found to be connected to the incidence of schizophrenia. Barr et al (1990) found mothers who had flu in the early months of pregnancy were more likely to have children who developed schizophrenia later on (onset is from puberty onward), suggesting a disease base for disorder.

Genetic Factors

Another biological theory of physiological malfunction causing mental illness is thought to be programmed into genetic material from paternal transference ( both parents passed their genes onto the child, including mental illness)

The best way of testing for genetic inheritance is to compare close relatives with the general population for occurrence of a particular disorder, and the closest genetic relation available is that of a multiple birth (twins for example) from the same genetic mix (same egg and sperm that has fertilised - or monozygotic - mono, meaning one and zygotic, is from another word for a fertilised human egg -zygote). Monozygotic twins, are then compared to di-zygotic (di meaning two - so from two eggs/two sperm, as any other siblings).

  • Monozygotic (MZ) - one egg, one sperm, sometimes referred to as identical

    Monozygotic twins.

  • Dizygotic (DZ) - two eggs, two sperm, (DZ) sometimes referred to as non-identical or fraternal twins

    Dizygotic twins.

The theory is, that if MZ twins have a high rate of similarity (concordance rate), then this must mean, there is a genetic link with the disease, as MZ are thought to share practically the same genetic mix, though recent research suggest, they are not as identical genetically, as first imagined . A geneticist (Carl Bruder 2006) from the University of Alabama, found there were many variations when comparing the genes of 19 sets of MZ twins .

Studies have found disorders such as phobias to have a low concordance rate and schizophrenia to have a high concordance rate. This means there is a genetic link assumed, with high concordance, so if you have a close member of the family with schizophrenia, you are more likely to be susceptible to the disorder, than if a close relative had a phobia.

Kendler, Masterson & Davis (1985) found relatives of schizophrenics were 18 times more likely to be diagnosed with schizophrenia than found randomly.

Gene-mapping is a way of investigating if people in the same family will contract particular disease or malfunction. Through gene mapping, specific genes have been implicated in some disorders. Sherrington et al (1988) found a link between schizophrenia and a gene located on chromosome 5, but the study has not been replicated, so the data is not very strong evidence.

As well as twin studies, the researchers will also do adoption studies of twins and family studies, such as Kendler et al 1985, already mentioned.


This includes hormones and neurotransmitters, which have been shown to have a significant impact on behaviour. It is commonly known that hormones have an impact on mood and behaviour. In both genders the impact of fertility hormones are well known, in males testosterone is thought to cause high levels of aggression and in females the monthly cycle of oestrogen and progesterone have been known to cause severe mood swings and extreme behaviour.

Neurotransmitters are also known to have an impact on behaviour, such as high levels of nor-adrenaline and dopamine are seen when a depressed mood is evident. Serotonin is thought to cause high anxiety, when there is too much available. Hormones and neurotransmitters in the right balance do not cause ill effects, but the biological approach suggests it is when there is an imbalance that behaviour and mental health is affected.

(Student hint - make sure you know your hormones and neurotransmitters, they are very important and are implicated in the majority of mental disorders in some way, from major illness to minor problems. The endocrine system, which is the release of hormones and neurotransmitters interacts with the nervous system causing various effects, such as the physiological stress response.)

Genetics are thought to have a significant impact on the levels of hormones and neurotransmitters, which tell the body how to function, so when explaining mental disorder from a biological approach, genetics can be linked to bio-chemistry.


Neuro-anatomy or brain structure is another key factor in mental illness and again, like the bio-chemical explanation is thought to be affected by genes, which may determine the structures of the brain. In schizophrenia, one of the common symptoms is the presence of enlarged ventricles and this is thought to be inherited, but it is not clear whether the structure is pre-determined (genetic) or is an outcome of the disease itself.

In people with autism for example, the cerebellum is much smaller than someone without the disease, as this disease is generally found quite early in life, it is very possible, the shrunken cerebellum is inherited.

In some people with eating disorders, it is thought the hypothalamus is defective and causes either over or under-eating.

There are many links in various diseases to neuropathology.

The biological model approach also uses the medical model to diagnose and assess and works as follows;

It is the same as the medical model in physical disorders and follows the medical model of diagnosis;

  1. Identify symptoms
  2. Diagnose symptoms using classification system
  3. Prescribe a suitable treatment

Student task

(Make up a table of the biological model of abnormal psychology, giving definition of how each aspect explains mental health/illness, then the research supporting the idea, then strengths and weaknesses of each. After you have read the rest of this section, add treatments too. It would be a good idea to do this with each approach.)





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