One explanation of sleep walking comes from the psychodynamic approach. The suggestion is that sleep walking helps to channel unconscious anxieties, which our worked through in our dreams and which can spill over into NREM sleep and channelled through motor activities. An additional psychodynamic explanation is that sleep walking represents a desire to sleep where one did as a child.
One problem with psychodynamic explanations of SW is that it relies on the subjective interpretation of the researcher, lacking objectivity and therefore reducing validity. Whilst one researcher may interpret the acting out of dreams to represent a particular unconscious anxiety, others may reach different conclusions about the anxieties being expressed. Moreover, as the unconscious mind is an abstract concept that is not measurable, this explanation is impossible to falsify. It is therefore difficult to confirm that SW is indeed a manifestation of unconscious anxieties.
Nevertheless, such explanations at least account for both the influence of nature (unconscious drives) and nurture (childhood experiences), unlike biological explanations which emphasise nurture. Such explanations therefore consider the complexity of human behaviour. Additionally, psychoanalytic therapies are often effective for treating a range of conditions, and thus if unconscious anxieties were responsible for SW, free association and other such techniques may be effective with regards to resolving such anxieties.
Genetics may also be able to explain sleep walking. EEG recordings during sleep walking show a mixture of delta waves characteristic of SWS and higher frequency beta waves which are characteristic of the awake state. It seems that sleep walking occurs when an individual is awakened from SWS but arousal of the brain is incomplete. Such abnormal arousal is likely to be genetic.
A02 Broughton Prevelance SW relatives
Support for the role of genetics comes from Broughton (1968. It was found that the prevalence of SW in first-degree relatives of an affected subject is at least 10 times greater than in the general population. This supports the suggestion that SW may indeed be genetic.
A02 Lecendreux concordance
Support for the role of genetics comes from Lecendreux et al. (2003. They reported 50% concordance rates in MZ twins compared with 10-15% in DZ twins. This supports the idea that genetics may cause sleep disorders such as SW which may help with the diagnosis of such disorders.
A02 Never 100%, environmental factors
Conversely, twin studies never report 100% concordance rates which indicates that SW cannot be purely genetic and that environmental factors must also contribute to the onset of SW. Thus, whilst the genetic explanation emphasises the role of nature, it is likely to be an interaction of nature and nurture factors, whereby individuals may have inherited a susceptibility, but this will only occur when triggered by an external factor, such as increased arousal due to stress.
A02 Zadra et al sleep deprivation
Further implications of a genetic explanation, comes from a study conducted by Zadra et al. (2005).They found that sleep deprivation is characteristic of individuals who are genetically predisposed to sleep walking. This may have important implications, assisting in the diagnosis of this sleep disorder.
However, research such as Zadra et al. (2005) takes place in an artificial sleep lab and therefore lacks ecological validity as findings may not reflect real life behaviours. It may be the case that sleep deprivation would not have increased SW behaviours so dramatically if individuals were their own home, as the strain of unfamiliar surroundings may have exacerbated this.
Understanding the causes of SW is essential as research into SW has important real-life applications. A case that was taken to court in 2003 involved a 32 year old male attacking and killing his father during SW, and was found not-guilty due to insanity and sent to a psychiatric hospital. This highlights the importance of understanding the causes and nature of disorders such as SW to prevent miscarriages of justice within our criminal justice system.
A02 Linked between alcohol, SW criminal justice sy
Related to this, voluntary intoxication has been used as a defence in criminal trials and ****. It is therefore important to understand the links between alcohol and SW, as this will again have important implications for the criminal justice system.
Lastly, it is fairly pessimistic to explain disorders such as SW from a biological perspective, as this is deterministic. If such disorders are indeed genetic, we have no free-will or control over our own behaviours, which may be discouraging for sufferers of SW. Whilst a genetic vulnerability may assist with diagnosis, the suggestion that this is predisposed may not be useful with regards to treatment.