This suggest that depression must be passed on through genes if there is a high concordance rate between twins which share the same genetic makeup both having depression. However, biological factors such as the amine hypothesis states that if amines such as serotonin and noradrenalin become unbalanced, they can lead to depression. PET scans support this idea as they show that low levels of serotonin are present in people that are depressed. Other supporting evidence is that drugs such as MAOI’s, which work by increasing the available amount of noradrenalin in the brain, were found to be effective in alleviating the symptoms of depression. A problem with this is that it doesn’t state whether it is cause or effect.
E.g. depression has been associated with decreased availability of serotonin. Genetics are another aspect to the physical features of the biological approach. Many psychological disorders occur more frequently in identical (monozygotic) twins than they do in non-identical (dizygotic) twins, and other disorders
The fact that both twins wouldn’t always develop schizophrenia means that another factor must be involved, for example family environment. Too much or too little of a particular neurotransmitter may produce psychological disorders. For example, an increased level of dopamine is linked to schizophrenia, and drugs like cocaine, which increase dopamine levels, can lead to schizophrenia like problems. Also, depression can be effectively managed and often treated with drugs that manage serotonin levels in the brain. However, Watson et al found that low serotonin levels may in fact be due to environmental factors.
The biosocial approach explains gender dysphoria as a disorder which is caused by an interaction between biological and psychosocial factors. The biological component of the biosocial theory of gender dysphoria is explained through the brain sex theory. The theory suggests that people experiencing gender dysphoria may have brain areas more typical of the opposite sex which stem from pre-natal hormones. The BSTc is larger and more densely packed with neurons in males than in females and males have around twice as many somatostatin neurons than do women. It is thought that these brain differences cause differences in the behaviour of males and females and could provide insight into the cause of gender dysphoria.
Anti depressants such as MAOI’s which increase the available amount of nor adrenaline in the brain, were found to be effective for elevating the symptoms of depression. So when noradrenalin is increased in the brain, symptoms of depression get better, suggests that it is chemicals that are the root cause of depression. This idea is also found in the results of taking reserpine, a drug used to treat high blood pressure. Depression is a unwanted side effect of this drug, as this drug acts by lowering levels of nor adrenaline. So again strongly suggests that low activity noradrenaline, is a factor contributing to the cause of depression.
A range of biological explanations for human aggression exists in psychology. One of these is the link between genetic factors and aggression. This explanation claims that aggressive behaviour is caused by the genetics passed down to a person and that certain genes predispose a person to be aggressive. This view has support from Sandberg (1961) who identified the XYY karyotype. This is an abnormality in the set of chromosomes found in men- instead of the normal 46 chromosomes men with the XYY gene will have 47.
Critical Point 3: There is a flaw with one of the key pieces of evidence to support the dopamine hypothesis. The drugs used to treat schizophrenia by blocking the dopamine receptors can actually increases it as neurons struggle to compensate for the sudden deficiency. Haracz, in a review of post-mortem studies of schizophrenics, found that most of those studied who showed elevated dopamine levels had received antipsychotic drugs shortly before death, unlike post-mortem of schizophrenics who hadn’t received medication these results showed that these individuals had normal levels of dopamine. Therefore, this evidence weakens the support for the dopamine
al., showed that identification of facial expression and emotional prosody is likely to be impaired in those diagnosed with paranoid schizophrenia. The study involved 25 in-patients who had paranoid schizophrenia, 25 normal control participants, and 25 depressive in-patients. Those with paranoid schizophrenia performed worse than the other two groups. The study supported other previously made hypotheses and seemed to be accurate. However, the study could have used more patients to ensure even greater accuracy.
Also Senksy found it helped with both positive and negative symptoms, and patients continued to improve after the therapy course had finished. CBT only treats the symptoms of schizophrenia; it doesn’t actually deal with the cause. Also, many patients become dependent on their therapist, and can relapse if they don’t have regular sessions. The biological model explains schizophrenia through biological faults, for example viral infections and brain abnormalities. Some psychologists say that schizophrenia can be inherited from their parents.
Nature vs. Nurture Scientists believe that traits such as hair and eye colour are determined by specific genes encoded in each human cell. They now also believe abstract traits such as intelligence, personality, aggression and sexual orientation are also encoded in an individual’s DNA. This is known as the Nature theory, whereby it is the genetics and the characteristics that have been inherited from generations earlier that make the person behave the way they are. The Nurture theory however has a different approach to human behaviour, and although it does not completely discount genetic tendencies, the scientists studying this theory ultimately believe that genetics do not matter. They argue that our behavioural aspects originate only from the environmental factors of our upbringing.