The Effect of Anxiety on Sleep Quality

The aim of this study was to extend the work done by Norlander, Johansson & Bood (2005), Jansson-Fröjmark & Lindblom (2008) and Bieling et al (1998), by investigating whether students who reported high levels of anxiety also reported poorer quality of sleep. Participants were Undergraduate Psychology students across all Monash University campuses including 180 male students and 306 female students. Participants were required to fill out questionnaires in order to obtain a score for state anxiety, trait anxiety and sleep quality. As predicted and supporting previous research, state anxiety did in fact have positive effect on sleep quality; however this was only when the effects of trait anxiety were not controlled. When the effects of trait anxiety were controlled, as predicted in the second hypotheses, the significance of the effects was removed. It was further found that when trait anxiety was controlled, the correlation between state anxiety and sleep quality was negative.

Sleep is an inevitable physical and neurological requirement for the optimal functioning and survival of humans. It is important for both the effective mental functioning as well as physical functioning of individuals (Norlander, Johansson & Bood, 2005). Its importance in terms of emotional well being has been a wide area for research in the past as well as in the present (Mellman, 2008). Insomnia is an intense inability to sleep which impairs the daily activities of the individual experiencing it in terms of cognitive functioning as well as sociality and other areas. It has become one of the most prevalent sleep disorders in both the general population as well as among psychiatric patients (Atalay, 2011). Particularly in terms of the field of psychology, this area is researched intensively as it is a symptom which many patients diagnosed with other psychiatric disorders such as schizophrenia, anxiety disorders, depression disorders and so on, tend to experience simultaneously (Buysse, Reynolds, Monk, Berman & Kupfer, 1988).

The quality of sleep which one gets is hindered by high levels of stress or anxiety which one may experience within their lives. Because there has been such wide research in these areas, questionnaires which allow for individuals to subjectively reflect on their feelings of anxiety or quality of sleep have been designed. To measure the quality of sleep, the Pittsburgh Sleep Quality Index was designed in which individuals can subjectively report issues with sleep using a likert scale to give them an overall score for their quality of sleep (Buysse et al, 1988). The State- Trait Anxiety Inventory is a questionnaire which has been designed to allow individuals to once again subjectively answer questions using a likert scale to gain an overall score in terms of state anxiety as well as trait anxiety (Bieling et al, 1998). State anxiety is a normal response to environmental demands or in other words, it measures the anxiety which the individual is feeling at the present time whereas trait anxiety is more to do with the actual personality of the individual and the manner in which they respond to environmental demands. In other words, trait anxiety is how the individual generally feels and is a more permanent anxiety characteristic of an individual.

In one research study conducted by Norlander, Johansson & Bood (2005), 91 individuals of which 50 were considered to not have stress and anxiety related problems whereas 41 were

considered to have such problems, were asked to complete questionnaires to denote depression and anxiety, stress and negativity/positivity. They were also asked to complete a questionnaire which required them to answer questions in order to gauge the level of the sleep quality they experienced. It was found that the participants who were considered to be more positive in terms of personality and who seemed to not be experiencing stress related problems and anxiety seemed to report better quality of sleep when compared with individuals who were experiencing stress, anxiety and other related problems.

These results have further been supported by the works of Jansson-Fröjmark & Lindblom (2008). In their study, similarly to the aforementioned study, the researchers asked participants to fill out similar questionnaires. In support of the previous results, the researchers found that once again participants with higher anxiety or depression levels reported higher levels of insomnia and vice versa. A problem however with this study was that the participants who were classified as having insomnia were not actually clinically diagnosed with insomnia in accordance with the DSM-IV diagnostic scale, leading to the term insomnia being loosely used to label participants experiencing poor quality of sleep.

In a different research study, researchers, Bieling, Antony & Swinson (1998) found in particular, trait anxiety to positively correlate more strongly with sleep quality when compared with state anxiety as trait anxiety can be linked to other symptoms such as depression.

The aim of the present study was to extend the work done by Norlander et al (2005), Jansson-Fröjmark & Lindblom (2008) and Bieling et al (1998), by investigating whether students who reported high levels of anxiety also reported poorer quality of sleep. Two hypotheses were therefore made with regards to the current study. Consistent with past research, one hypothesis was that there would be a positive correlation between state anxiety and quality of sleep without controlling the effects of trait anxiety. On the other hand it was hypothesised that after controlling for the effects of trait anxiety, the positive correlation between anxiety and quality of sleep would cease to be significant.

Method

Participants

The sample consisted of 486 undergraduate Psychology students across all Monash University campuses. There were 180 male students and 306 female students who participated voluntarily during their Psychology class time.

Materials

1. The State Trait Anxiety Inventory (STAI) (Appendix A)

This measures both state components as well as trait components of anxiety to enable the distinction between an individual who is usually calm but experiencing a high level of anxiety at the present time to an individual who is generally in a high state of anxiety. Higher scores on this inventory correlate to higher anxiety levels. It comprises of two 20 item scales to measure the level of anxiety triggered by the emotional state of the individual (State/S-anxiety) and the individual differences in proneness to anxiety as a trait in personality (Trait/T-anxiety). Participants were required to report their feelings of anxiety at the current time (i.e.: 'right now').