The levels of Cortisol that have recently been mentioned are seen by some researchers to have a great effect on depression and mood. Barlow and Durand (1995) discovered that levels of Cortisol seem to be lower in that of depressed patients in comparison to ‘normal’ people. Carroll et al (1980) also looked into this and found that by using dexamethasone to suppress Cortisol, the amount present in an individual could be measured. It was found that in ‘normals’ about 50% would be suppressed, however in those people suffering from depression, very little suppression was shown. This could indicate that the level of Cortisol could be causing depression, it could however be that the high level of Cortisol is the result of the depression rather than the cause. It must also be mentioned that such high levels of Cortisol were also recorded in patients suffering from anxiety and other mental health disorders.
Another hormone that is seen to be a factor by many is Serotonin. Serotonin regulates emotional reactions and makes sure that neural activity is modulated. If Serotonin levels are not as they should be then it allows wild variations in neural activity. Through advances in technology, this can be observed using PET Scans. There are certainly a number of studies that seem to indicate that Serotonin levels affect the mood of a person. Lam et al (1996) found that drugs containing Serotonin were effective when treating those suffering from Seasonal Affective Disorder.
Another psychological idea is that of genetic transmission – this theory would mean that depression could be inherited from parents to children etc. With this premise studies seem to show mixed results. There are numerous twin studies comparing monozygotic (MZ) twins to dizygotic twins (DZ), most of these seem to provide quite convincing evidence, for example, when looking at depression, McGuffin et al (1996) researched 109 twin pairs and found a concordance level of 46% with MZ twins, compared to 20% in DZ twins providing support for this theory.
There are also a number of studies that observe those families containing an individual suffering from depression in order to try and find evidence of genetic similarities. DSM-IV states that there is a high level of individuals suffering unipolar depression, who have parents that suffer from bipolar depression. Of course cases where close family members of those depressed (such as brothers, sisters and parents) suffer from depression themselves at a later date, must be looked at with caution as the depression could be a reaction to living directly with a severely depressed person or simply learned behaviour.
In contrast to the physiological ideas, it can be argued that psychodynamic concepts such as Freud’s seem to answer some questions regarding the development of depression. Freud argued that depression is like grief and that it would occur as a reaction to a loss of an important relationship. The person would repress anger and direct it inwards in the form of self-hatred and self-accusation thus reducing self-esteem and making the person vulnerable to depression. This theory would also mean that a loss as a child or a negative relationship with parents could be repressed and affect the person in adult life in the form of depression. Bifulco et al (1991) studied 250 women who had lost their mothers before 17yrs old. It was discovered that the risk of depression was twice as high compared to the general population.
Lewinsohn (1974) suggested that depression occurs when an individual has a lack of reinforcement or reward. Similar to Freud’s theory, this idea works around the basis that most relationships are a major part of positive reinforcement and therefore the loss of one would cause depression. Obviously once the individual displays depressive characteristics; this is often positively reinforced in the form of others giving sympathy and concern, which could in turn make the individual more likely to stay in a depressed state.
It is true that many people do seem to suffer from depression after a loss of some description, but it cannot be denied that depression also occurs when there has been no loss in the person’s past. The idea of positive reinforcement being gained through seeming depressed would not explain why the individual would remain depressed once sympathy from others had decreased.
Another behavioural concept is Learned Helplessness. When looking at this we must understand depression may be due to an individual experiencing a stressful situation that is out of their control. Seligman (1975) carried out research with dogs to look at this theory. The dogs were trapped in cages and were given small electric shocks, half of the caged dogs were able to stop the shocks, however the other half were not. The dogs were then placed in a new cage- one half of the floor was electrified and would administer the dog with shocks, over a barrier/wall the other side of the floor was not electrified. It was noted that in almost all cases the dogs that had been able to stop the electric shock in the first cage learned to jump over the wall and to therefore cease the electric shocks. The dogs that were unable to stop being shocked in the first cage often did not attempt to escape from these shocks and simply lay cowering. The dogs unable to stop the initial shocks had learned that their attempts had been useless and therefore seen it as pointless to try and escape. It was suggested that the human mind could work in a similar way
This experiment was criticised though as it must be remembered that when a patient suffers depression there are many social factors that often need to be taken into consideration. Although understandably, it would have been difficult to administer social aspects into the experiment, ultimately these may have an influence.
A cognitive/behavioural theory that depression occurred as a result of negative thinking was developed by Beck (1967). Beck called these negative thoughts ‘cognitive errors’. Beck (1991) added to his research in suggesting that there were three main parts of depression, which he named the ‘cognitive triad’, which consisted of the person holding negative views of themselves, their experience in the world and the idea that any future experiences would be negative.
Beck argued that these components would lead to the individual having automatic negative thoughts such as ‘I am useless’, leading to depression. Beck also argued that this way of thinking could be a result of a traumatic event/s or negative treatment during childhood.
It can be seen that most of the theories looked at have had research carried out in order to support them. When looking at the psychodynamic and behavioural approach a large amount of research seems to suggest that depression can occur due to a loss or lack of reinforcement or even due to a traumatic experience, yet a lot of the research can be viewed to be unreliable – for instance when looking at the idea of Learned Helplessness, Seligman did seem to prove this theory to a point, however only with dogs, it must be taken into consideration that humans are extremely different to other mammals and it cannot be said that what applies to one applies to the other. The negative aspects of the physiological theories are also present however, many hormonal changes may not be necessary because of the depression suffered, but could be an effect of the illness. In conclusion, it would appear that depression is a physiological illness to a degree, whether caused by outside factors such as loss or trauma or by genetics, some hormone levels do seem to fluctuate causing the mood in a person to change and therefore depression is often treated with medication.
Bibliography
Cardwell (M) et al (2000) ‘Psychology for A Level’ London: HarperCollins Publishers
Eysench (M) & Flanagan (C) (2002) ‘Psychology for AS Level’ Sussex: Psychology Press Ltd
Gross (R) et al (2004) ‘Psychology a new Introduction’ Kent@ Greenbridge Publishing Services
