A01 Neural mechanisms, innate biological inherited
The neural mechanisms controlling sleep, including the hypothalamus and neurotransmitters such as serotonin and melatonin are likely to cause primary insomnia. Malfunction in our sleep control systems may be responsible for sleep disorders such as Insomnia. Moreover, these innate biological rhythms are likely to be inherited, particularly as idiopathic insomnia (a form of primary insomnia) does not vary with arousal level, suggesting a genetic cause of insomnia.
A02 Watson et al - twin 50% variance, genetic fact
Support for a genetic explanation comes from Watson et al. (2006) who conducted a twin study and found that 50% of the variance in the risk for insomnia could be attributed to genetic factors. This supports that idea that genetic vulnerability is a predisposing risk factor of Insomnia.
A02 Lack generalisability, reductionist, enviromen
Conversely, one has to acknowledge that support from twin studies may lack generalisability, as obtaining samples of MZ or DZ twins with sleep disorders would be relatively difficult and would yield a small sample which may not be representative of the target population. Indeed, unless they were MZ twins reared apart, if Insomnia did occur within a set of twins, it may instead be explained by similar upbringing.
A02 Application, drugs
If neural mechanisms are responsible for Insomnia, sedatives, anti-anxiety drugs and melatonin may be recommended as a short-term solution. However, the use of drugs could cause side-effects such as daytime drowsiness, could lead to dependency on medication and also do not address the cause, they simply treat the symptoms. Thus, whilst they may only be used as a quick fix, there are arguably more effective treatments available. Indeed, whilst they can increase the amount of sleep, they reportedly reduce the quality of sleep.
Parasomnias (sleep disorders characterised by behaviours and events occurring during sleep) are a cause of secondary insomnia. Sleep Apnoea, a disorder characterised by disruption of breathing during sleep, leading to increased awakenings throughout the night can cause insomnia. Likewise, sleep walking, which disrupts normal sleep can lead to the development of insomnia (secondary insomnia).
A01 Issues with treatment, inappropriate to target
This highlights the important issue of being able to distinguish between primary and secondary insomnia, in order to be able to provide an effective treatment. It may therefore be inappropriate to prescribe drugs to target symptoms of insomnia, if an alternative condition or disorder is responsible for the Insomnia. Indeed an understanding of available treatments is imperative.
A02 Roberts, teens and drugs, causes
Research has also shown that teenage insomnia is a major problem in teenagers (Roberts, 2008). It is possible that teenagers turn to drugs as a means of dealing with their sleep problems and therefore one must consider the causes of Insomnia and effective treatments available for adolescents to reduce this problem.
A02 Personality, Marin et al, Anxiety 40%
Personality can explain primary insomnia. Anxiety is associated with high levels of physiological arousal which acts against any tendency to sleep. Neuroticism is a personality trait that is significantly correlated with anxiety. Subsequently, anxious individuals are more likely to suffer from insomnia. With regards to secondary insomnia, psychological disorders such as depression and anxiety states are associated with insomnia. It has been estimated that around 40% of patients seeking treatment for insomnia have an associated psychological disorder (Morin et al., 1999).
A02 Vahtera et al, support anxiety
Research conducted by Vahtera et al. (2007) provides support for Anxiety being a cause of Insomnia. They found that vulnerability to sleep disorders following traumatic life experiences, such as divorce is highly correlated with the personality trait of anxiety. This supports the idea that anxiety and therefore personality may cause Insomnia, due to difficulties of coping with stress-inducing events.
A02 Ohayon and Roth, cause of mood disorders
However, further research opposes the idea that insomnia is secondary to other causes. Ohayon and Roth (2003) studied almost 15,000 Europeans and found that insomnia more often preceded mood disorders. This suggests that rather insomnia resulting from depression or anxiety, it could instead be the cause of such mood disorders.
A02 CBT supports nurture
Conversely, further support for the suggestion that anxiety causes Insomnia comes from the effectiveness of Cognitive Behavioural Therapy and muscle relaxation. Since such techniques effectively reduce arousal and anxiety, they highlight the important role of anxiety in the development of sleep disorders. Conversely, this suggests that faulty cognitions as opposed to a genetic disposition are responsible for the anxiety which can cause Insomnia. The suggestion that rational cognitions can be learned, supports the nurture side of the debate, which may be encouraging for sufferers of Insomnia.
A01 Sleep hygiene
Treatments such as sleep hygiene, which involve increasing healthy sleeping habits such as sleeping in a darker room, reducing caffeine consumption and increasing exercise are likely to be effective since sufferers adopt strategies such as increasing consumption of caffeine and reducing exercise to cope with their lack of sleep and thus decreased energy levels.
A02 Gender Bias
There is a gender bias, specifically a beta-bias with regards to research into insomnia, since studies have not researched differences in sleep disorders between men and women. It may therefore be invalid to draw conclusion from research investigating males, for example, since there may be different causes of insomnia in men and women. It could be the case, that hormonal changes are more responsible for Insomnia in women.