- Education and Science
Psychology A2 - A Grade Essays - Biorhythms
Discuss Explanations for Insomnia (24 marks)
There are two main types of insomnia – primary insomnia, where there are no underlying medical/physiological conditions causing it and secondary insomnia where the insomnia is a symptom of another underlying psychological/physical disorder. Primary insomnia has no obvious cause, but there are some factors thought to be influential in its development – for example genetics. There is evidence that mutated genes in mice lead them to sleep 50-60% longer than controls, which is supported by research that found that 37% of insomniacs have a primary relative who also suffers from insomnia.
There is evidence that insomnia is caused by a change in neurochemistry – those with chronic insomnia lasting 6 months or more showed reduced levels of GABA, a neurotransmitter involved in reducing brain activity – this could mean that insomniacs find it hard to fall asleep as their brains are more active than people who don’t suffer from insomnia. However, this difference in brain chemistry in insomniacs was measured after 6 months from the onset of the disorder and thus it is possible that the change could be due to a lack of sleep, and so is hard to determine cause and effect.
Secondary insomnia is where there is a single, underlying medical, psychiatric or environmental cause to the sleep disorder. For example insomnia is often a characteristic symptom of illnesses such as depression or heart disease. It is also typical of people who do shift work or who have circadian rhythm disorders such as phase delay syndrome. It also may be the result of environmental factors such as too much caffeine or alcohol. There are also risk factors that influence insomnia such as age, gender, sleep apnoea and personality. Older people and women are more likely to suffer from insomnia as well as people who internalise psychological disturbances and people who suffer from a pre-existing parasomnia.
Research evidence supports the idea that secondary insomnia can be caused by psychological problems such as depression and anxiety. Gregory et al conducted a longitudinal study that looked into the relationship between family conflict and the later development of insomnia. A group of children were studied with a wide range of variables taken into account. Questionnaires were used to measure family conflict, hostility and tension and it was found that the degree of family conflict experienced by the child between the age of 9 and 15 was significantly correlated with the frequency of insomnia at the age of 18. The study concluded that there is a casual connection between family conflict and later sleep problems such as insomnia and thus supports the idea psychological problems may cause secondary insomnia.
Despite supporting research evidence, over 60% of insomnia research conducted in sleep labs used male participants. This could be an example of beta bias, as the findings have been applied to females without adequate research into female insomniacs. This decreases the validity of the research as female hormones are different and this could affect the likelihood of insomnia developing. It was also found that women have higher incidences of insomnia than men, but this could be because they talk about it more and are more willing to get it diagnosed than men.
If research is potentially difficult to generalise to females then it may be harder to diagnose women with insomnia. The treatment that a person may receive for their insomnia depends on the type and degree of the disorder i.e. whether it is transient of chronic etc. If insomnia is secondary to a psychological disorder, such as depression, then drugs to treat the depression can be used to treat the underlying problem and thus the insomnia. If a person it experiencing primary insomnia because they are anxious when it comes to sleeping, due to expectations of having problems, then stimulus control therapy can be used to treat it. The trouble with treating insomnia in such a way is that it is often hard to diagnose the type/degree of the insomnia as there can be so many causes of it. This may lead to wrong diagnosis and thus the wrong type of therapy used which could leave the insomnia untreated. This in turn could lead the individual to be more anxious as they believe that it is untreatable which could enhance their insomnia further. The solution to this would be to treat the primary and secondary insomnia at the same time and take into account lifestyle, psychological and medical problems in a diathesis stress model. This would help to prevent misdiagnosis and treatment.
Describe and Evaluate Research studies into Infradian Rhythms (24 marks)
Infradian Rhythms repeat themselves over a greater period of time – rhythms that last longer than a day. For example, they may repeat themselves weekly, monthly or even annually (known as a circannual rhythm), for example, hibernation, bird migration and many reproductive cycles. An example of a human infradian rhythm is the menstrual cycle which is controlled by the pituitary gland (an endogenous pacemaker). The pituitary gland releases hormones which cause an egg in the ovaries to ripen and produce oestrogen. Once the egg has ripened the ruptured follicle starts to secrete progesterone which causes the lining of the womb to thicken and increase blood supply. If fertilisation and implantation in the womb does not happen around two weeks after ovulation then the womb lining will be shed. Whilst the menstrual cycle is a biological process that is universal, there are large individual differences such as the length of time and the age the menstrual cycle begins.
Several research studies have been done into Infradian rhythms, and how to regulate them. Infradian rhythms are governed by endogenous pacemakers (EP’s) and exogenous zeitgebers (EZ’s). One zeitgeber that helps regulate Infradian rhythms is the release of pheromones which are biochemical substances produced in the endocrine system, carried in the blood and then released into the air. One study used pheromones to synchronise women’s periods by taking the pheromones of one woman and applying them (mixed with alcohol) onto the upper lips of another group of women. The same procedure was done on a control group, but the mixture did not have pheromones init. The participants didn’t know whether they were in the experimental or the control group, to reduce experimenter effects. By the end of the experiment, 4 out of 5 women in the experimental group had menstrual cycles that synchronised within 24 hours of the donor’s. This shows that when several women live together (and do not take oral contraceptives), they tend to menstruate at the same time every month.
One study looked at the effect of EZ’s on the infradian menstrual cycle. It involved studying a woman who spent three months in a cave relying on only the dim light of a miner’s lamp. Her day lengthened to 24.6 hours but her menstrual cycle shortened to 25.7 days and it took a year for her cycle to return to normal after the study. This suggests that it is not just EP’s that influence infradian rhythms but EZ’s such as light can influence them too. It was also found that with 600 girls from northern Germany, the onset of menstruation at puberty was much more likely to occur during the winter months – this also suggests a link between light, the secretion of melatonin and the menstrual cycle.
Another Infradian rhythm linked to light and melatonin that affects some people is the Seasonal affective disorder. This disorder has a circannual rhythm to it, in which people suffer from depression in the darker winter months and recover during the summer months. It has been shown that melatonin is secreted by the pineal gland when it is dark and that there’s a positive correlation between the amount of darkness and the amount of melatonin that is secreted. It has also been suggested that increased amounts of melatonin may be related to chronic depression.
The understanding of the role of darkness in SAD has led to effective therapies such as phototherapy. This involves using very strong lights in the evening and/or early morning to change levels of serotonin and melatonin. Sufferers of SAD have reported that daily use of these lights has alleviated the symptoms associated with SAD such as depression and lethargy. However, it has been argued that the positive results of phototherapy may be due to the placebo effect where patients feel better because they believe that their condition is being treated. One study found that when sufferers of SAD were treated with a placebo they were less likely to report improvement, however 32% of them said that the ‘treatment’ had relieved their symptoms. This suggests that the cause of infradian rhythms, such as SAD, may not be solely biological but may also be caused by psychological factors. This means that the research into infradian rhythms may be reductionist as it only takes into account biological factors (such as levels of hormones and neurotransmitter) and not psychological, environmental or cognitive factors. Therefore it may be necessary to take a more holistic approach to studying infradian rhythms in order to get a better overview of how they are established and maintained.