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The current study investigated the role of trauma exposure, emotion regulation, and
neuroticism on sleep quality among postgraduate students. Four hundred and four postgraduate
students (males=228, females=176) participated in the study. The students’ ages
ranged from 22 years to 51years, with a mean age of30.60 years (SD=6.84).Participants
completed the Harvard trauma Questionnaire (HTQ), Difficulties in Emotion Regulation
Scale (DERS), Neuroticism Subscale of Big Five Inventory (NSBFI), and Pittsburgh Sleep
Quality Index (PSQI). Multiple regression was used for data analysis.Result showed that
trauma exposure significantly predicted sleep quality (β = .12, P <.05). Difficulties in
emotion regulation significantly predicted sleep quality (β = .38, P <.001). Neuroticism was a
significant predictor of sleep quality (β = .11, P <.05). Findings were discussed in relation to
the literature.It was suggested that there is need to consider traumatic events, emotion
regulation difficulties and neurotic traits in attending to individuals that have reduced quality
of sleep. Limitations of the study highlighted and suggestionsfor further study were




Title Page i
Certification ii
Dedication iii
Acknowledgments iv
Table of Contents vi
List of Tables ix
Abstract x
Statement of the Problem 15
Purpose of the Study 18
Operational Definition of Terms 18
Theoretical Review of Study Variables 20
The 3P Model of Sleep 20
Lundh and Broman Model of Sleep 24
Cognitive Model of Sleep 25
Espie’s Psychological Inhibition Model of Sleep 28
Stress Response Theory of PTSD 30
The Emotion Dysregulation Model 32
Digman’s Theory of Personality 34
Empirical Review 36
Trauma Exposure and Sleep Quality 36
Emotion Regulation and Sleep Quality 41
Neuroticism and Sleep Quality 45
Summary of Empirical Review 48
Hypotheses 52
Participants 53
Instruments 53
Procedure 58
Design/Statistics 58
Summary of Findings 63
Implications of the findings 66
Limitations of the study 69
Suggestions for future research 69
Summary 70
Conclusion 71
References 73
Appendices 90




Sleep is an essential and inevitable part of human life that influences optimal functioning.
In the literature, it is difficult to determine the underlying function of sleep because there are
likely many confounding factors with regard to causality (Hale, 2005). Various happenings
throughout the day may have an effect on the quality of sleep and the quality of sleep one has the
night before may have an effect on the many activities and interactions during the day. How
refreshed and awake an individual feels after a night’s sleep is in part determined by the sleep
quality an individual experiences. The body’s main biological restorative process is sleep. It is
considered to be both physically and psychologically restorative to an individual. Sleep is a time
that the body physically grows and repairs organs and tissues from normal wear-and-tear (Robles
& Carroll, 2011).
Sleep is also one of the essential components in the overall mosaic of health and it
profoundly affects the subjective sense of physical and mental well-being (Guilleminault,
2001). It is one of the things that exemplify the direct link between the physical and the
psychological state, which are mutually inseparable. Sleep is therefore a relevant issue for public
health and public policy (Williams, Meadows & Arber, 2010). Sleep appears necessary for every
system of the body to work properly (Odetola & Adejumo, 2014), and it is required to provide
energy for the physical and mental activities of all humans. Sleep is one of the most essential
needs of the body and mind, required by both the healthy and the ill individuals, but for sleep to
actually be beneficial to health, it must be adequate in quantity, quality and latency (Richardson,
Thompson, Chambers & Turnock, 2009). An old Chinese proverb states: “it is only when one
cannot sleep, that one knows how long the night is”. This explains the importance of sleep for
human functioning. Just as water and food are essential for human well-being, sleep is judged
essential for human survival.
Sleep is essential to the healthy development of adolescents and adults, as well as their
success at school and in the workplace. Sleep experts believe sleep affords the neurons that were
used while awake an opportunity to be repaired and restored. Without sleep, neurons may
become so depleted in energy or so polluted with bye-products of cellular activities that they
begin to malfunction (Salo, Vahtera & Hall, 2012). Sleep also gives the brain a choice to
exercise important neuronal connections that might otherwise deteriorate from lack of activity.
Thus, the need for sleep in human beings is universal and basic because sleep serves as a
restorative function for the body and mind. Sleep has a protective role in that it helps prepare
people for coping with daily hassles and life stressors (Walker & Vander Helm, 2009).
Though there is little medical basis for this belief, the amount of sleep that many people
believe they should get is about eight (8) hours (Goodman, 2014). Kripke, Garfinkel, Wingard,
Klauber and Marler’s (2002) study of more than 1.1 million adult participants examined the
amount of sleep each night, the number of nights with insomnia, and other controlling factors
such as medication use, demographics, health and habit. Participants who slept 6.5hrs – 7.4hrs
had the least risk for all-cause mortality in both males and females. Tamakoshi and Ohno’s
(2004) study of over 100,000 Japanese subjects also supported this notion that sleep duration of
about 7 hours has the lowest mortality risk. In a study with middle-aged and older adults in
Australia, short sleep durations (<6hrs) and not long durations (>9hrs) were associated with
lower self-reported health and quality of life (Magee, Caputi & Iverson, 2011). However, sleep
duration is not always enough when talking about sleep quality. Sleep habits are important for a
restful night and sleep quality remains an important habit of sleep (Augner, 2011).
Quality sleep is important in all individuals. Sleep quality is defined as one’s satisfaction
of the sleep experience, integrating aspects of sleep initiation, sleep maintenance, sleep quantity
and refreshment upon awakening (Krystal & Edinger, 2008). Although the construct of sleep
quality is widely used, a review of the empirical literature suggests that it is not yet fully
understood. Indeed, Akerstedt, Hume, Minors and Waterhouse (1994) noted that there seems to
be very little systematic knowledge as to what actually constitutes subjectively good sleep and
how this should be measured, thereby suggesting the relevance of increasing research on this
The quality of sleep is a measure of both the quantitative and qualitative components of
sleep. The quantitative component includes the duration of sleep, sleep latency or number of
arousals, while the qualitative component is a subjective measure of the depth and feeling of
restfulness upon awakening (Lavie, Pillar & Malhotra, 2002). The quantity of sleep an individual
gets is important, but it is the quality of sleep that they really have to pay attention to. Some
people sleep eight or nine hours a night but do not feel well-rested when they wake up because
the quality of their sleep is poor. The best way to figure out if adults meet their sleep need is to
evaluate how they feel as they go about their day. If an individual sleeps for long hours, he/she
feels energetic and alert all day long, from the moment he/she wakes up until his/her regular
Sleep quality is an important indicator of adults’ health and well-being (Tynjälä, Kannas,
Levälahti & Välimaa, 1999). Good sleep quality is associated with a wide range of positive
outcomes such as better health, less daytime sleepiness, greater well-being and better
psychological functioning, while poor sleep quality is one of the defining features of chronic
insomnia, (Edinger, Bonnet & Bootzin, 2004). Poor sleep quality has been associated with
increased tension, irritability, depression, confusion and generally lower life satisfaction (Pilcher,
Ginter & Sadowsky, 1997). Poor sleep quality contributes to poor daytime coping with daily
stress, and may increase fatigue, moodiness, or memory impairments and anxiety (Harvey,
Jones & Schmidt, 2003; Joo, Shin, Kim, Yi, Ahn & Park, 2005) and thus not functioning at
optimal levels (Gaultney, 2010). The belief that one has had high quality sleep regardless of
actual sleep quality may also be a factor in determining restoration from sleep. When a person
does not get an adequate amount of sleep, the loss in sleep contributes to health problems
because the body is unable to replenish the lost resources that are consumed during waking
In Nigeria, Odetola and Adejumo (2014) conducted a research on the effect of nursing
hospital routine on the pattern, quantity and quality of sleep among hospitalized patients in
Ibadan and the result revealed that there is a significant difference in sleep pattern before and
during hospitalization. This study provided an opportunity for nurses to appreciate the
importance of sleep (both in quality and quantity) especially for hospitalized patients as a vital
contribution to recovery and the need for a thorough assessment of patients’ sleep pattern which
is an important indicator of improving health in the general population.
Aloba, Adewuya, Ola and Mapayi (2007) acknowledged that the extent of sleep-related
problems remains largely an unidentified public health issue, particularly so in Africa where
there is inadequate personnel to assess sleep problems. Reid and Baker (2008) reported that
awareness of sleep and sleep disorders was low in the general population in South Africa.
Indeed, this observation can easily be generalized to other parts of the sub-Saharan Africa, in that
by comparison, South Africa is by far better developed in its education, health and all areas of its
economy and yet sleep and sleep disorders awareness is low (Reid & Baker, 2008). A wider
implication of this lack of awareness about sleep, is that in sub-Saharan Africa it is likely that
most sleep and sleep-related issues may be presented to primary care health workers as physical
Students have been identified as a population group particularly affected by problems
with sleep (Pallos, Yamada, Doi & Okawa, 2004; Carney, Edinger, Meyer, Lindman & Istre,
2006). A number of factors can influence sleep quality. Factors of interest to the researcher are
trauma exposure, emotion regulation and neuroticism.Majority of university students are in early
and middle stages of adulthood. This age group may have experiences of various types of
traumatic events (Davidson, Hughes, Blazer & George, 1991). Those with traumatic experiences
have frequent sleep disturbances interfering with their sleep quality. Due to the trauma they have
experienced, their sleep patterns and related problems could differ from students without trauma
(Fukuda & Ishihara, 2001).
A significant factor that may affect the sleep patterns of adults is the trauma they
experience like the major life events (e.g., domestic violence, divorce, rape, earthquake, accident,
war, death of a family member), and more minor but daily stressors (e.g., difficulties with
interpersonal relationships, work-related stress) can affect sleep patterns in otherwise healthy
individuals by heightening arousal before falling asleep and during nocturnal awakenings.
Nonetheless, the importance of sleep disturbance in victims of trauma has been that it has
prognostic significance (Harvey, et al., 2003), and therefore worthy to investigate in sleep
Trauma exposure is a construct that has and is still being studied among highly and
multiply traumatized populations including but not restricted to adolescents and adults in
communities, schools, and public health settings in different cultures; as well as among torture
survivors, prison inmates, minorities, refugees, and mental health patients ((Lambert, Ialongo,
Boyd & Cooley, 2005; Finkelhor, Turner, Ormrod, Hamby& Kracke, 2009; Stein, Jaycox,
Kataoka, Rhodes& Vestal, 2003). Trauma is a sudden, unpredictable, life-threatening event that
is out of the ordinary life experience, and may result from natural or accidental disasters
(earthquake, fire), large-scale catastrophes (war), medical trauma (stroke), and personal
catastrophes (rape, assault, witnessing violence) (Keane, Marshall & Taft, 2006). Experience
such as these often are considered extreme stressors.
The Diagnostic and Statistical Manual of Mental Disorder Fifth Edition (DSM-5, 2013)
describes trauma as direct personal experience of an event that involves actual or threatened
death or serious injury, or other threat to one’s integrity; or witnessing an event that involves
death, injury, or a threat to the physical integrity of another person; or learning about unexpected
or violent death, serious harm or threat of death or injury experienced by a family member or
other close associate. Trauma not only entails physical injuries, but also includes psychological
effects from stressful events (Frommberger, Angenendt & Berger, 2014). Immediate threats
during such experiences may result in death or injury.
Exposure of adults to trauma is pervasive in most parts of the world (Finkelhor, et al.,
2009; Clever & Bruck, 2010; Adebajo & Kolawole, 2013). Nearly 80% of adults seen in
community mental health clinics have experienced at least one incident of trauma during their
lifetime, representing roughly five out of every six adults (Breslau & Kessler, 2001).Exposure to
a traumatic event includes individuals either experiencing or witnessing an event during which
they experience intense fear, helplessness, or horror (APA, 2000).Further, exposure to trauma
can occur through various means, including direct victimization, witnessing or hearing violent
acts, and media violence (Buka, Stichick, Birdthistle & Earls, 2001). Exposure to traumatic
events is quite common, with estimated lifetime rates ranging from 26% to 92.2% in men and
from 17.7% to 87.1% in women (Creamer, Burgess, & McFarlane, 2001).Traumatic events that
may trigger PTSD include violent personal assaults, natural or unnatural disasters, accidents, or
military combat, Boko Haram insurgency, terrorism or mass disaster, violence or war, or may
involve a move to a new location, death of a friend, family member, or pet, divorce or separation
or jilting, ssfear, anxiety, hospitalization, loss of trust, pain, physical injury or illness, separation
from parents, or perceived abandonment. Of course, violence and mortality rates have been
estimated at 3.2 to 9.5 per 10,000 per day, with the majority of these caused by attacks which
caused people to flee their home (Depoortere, Checchi & Broillet, 2004; Grandesso, Sanderson,
Kruijt, Koene, & Brown, 2004).
At the time of a traumatic exposure, the victim might feel numb and incapable of
appropriate response. Thereafter, memories of the trauma engender feelings of helplessness, fear,
or horror, akin to re-experiencing the trauma time and again. In children, signs of anxiety might
include an increased need for physical and emotional closeness, fear of separation, difficulties
sleeping, loss of appetite, bedwetting, or changes in interactions with others. Thus, it is
imperative to discuss the events and feelings that accompany them in order to resolve the feeling
and move forward.
The emotional aftermath of traumatic events can be devastating as any physical damage.
Whether trauma stems from a personal tragedy, a natural disaster, or other overwhelming life
experiences, it can shatter one’s sense of security, making one feel vulnerable, helpless, and even
numb. There is no right or wrong way to feel after traumatic exposure. But there are many
strategies that can help a victim work through feelings of pain, fear, and grief and regain his/her
emotional equilibrium. Whether the traumatic event happened years ago or yesterday, the person
can be healed and he or she moves on. Therefore, after a traumatic exposure, the victim needs
time, support, and a sense of safety to re-establish trust.
Most research about trauma exposure in adults have examined the association between
adverse outcomes from specific trauma exposures such as sexual abuse (Berliner & Elliott,
2002), domestic violence (Adebayo & Kolawole, 2013), physical abuse (Christian, 2015), or
community violence (Gaylord-Harden, Dickson & Pierre, 2015). However, exposure to trauma is
not necessarily a one-time occurrence, and students who are exposed to a single trauma are at far
greater risk of experiencing multiple exposures of trauma and violence (Finkelhor, et al., 2009).
Research (Daigre, Rodriguez-Cintas, Rodriguez-Martos, Grau-Lopez, Berenguer, Casas
& Roncero, 2015; Sneed, 2015; Stanley, 2011) showed that multiple trauma exposures such as
sexual and physical abuse, neglect, exposure to domestic violence, and assaults by peers, have
been associated with a wide range of later psychological symptoms. One of such symptoms may
be sleep-related disorders or sleep disturbance as a symptom of another disorder. Trauma can
interfere with sleep onset, maintenance and quality of sleep. Sleep disturbances are common in
trauma survivors, and they can exacerbate depression and PTSD, increase symptomatology, and
have a negative effect on health (Krakow, Artar, Warner, Melendez, Johnston, Hollifield,
Gemain & Koss, 2000). Several studies have suggested possible links between traumatic
experiences and sleep quality such as women who experienced perinatal and postpartum
outcomes, sexual and physical abuse, and exposure to natural disaster(Noll, Trickett, Susman &
Putnam, 2006; Tempesta, Curcio, De Gennaro & Ferrara, 2013; Swanson, Hamilton & Muzik,
2014; Hauff, 2015).
Reactions to traumatic events vary considerably, ranging from the relatively mild, which
create minor disruptions in the person’s sleep quality, to the severe and debilitating. It is
common for those who are exposed to trauma to experience intrusive thoughts and images,
accompanied by attempts at avoidance, emotional numbing (such as sleeping difficulties or
anger) (Joseph, 2010). Highly stressful and traumatic events typically produce a variety of
cognitive, emotional, behavioural, and social elements that influence the eventual outcome. A
common theme in models that focus on the aftermath of these significant life events is the impact
of rumination that occurs (Calhoun, Cann, Tedeschi & McMillan, 2000). The ruminative
thinking that goes on after a traumatic or stressful event has been often considered to be
negative, depressogenic, and intrusive thinking that may dominate the survivors’ experience as
they focus on the harm they have experienced. Therefore, trauma exposure could be enormous
scientific value in studying sleep quality among graduate students who are potentially exposed to
The second predictor of sleep quality to be examined in the study is emotion regulation.
The most frequently cited reason why people do not have a good quality of sleep is the negative
emotion associated with life events they experience (Watson & Clark, 1991). The need to
regulate these emotions to positively impact sleep quality becomes imperative.Emotion
regulation has been defined as a set of emotional, cognitive, behavioural and interpersonal skills
which regulate and moderate the experience and expression of human emotions (Posner &
Rothbart, 2002). Similarly, Forbes and Dahl (2005) describe emotion regulation as “… the
internal and external processes involved in the initiation, maintenance, or modification of the
quality, intensity, or chronometry of emotional responses” (Forbes & Dahl, 2005, p. 5). Perhaps
a more colloquial description of the construct is one reported by Gross (1998) who states that
people regulate their emotions deliberately through their thought and behaviours or automatically
outside of awareness in an attempt to modulate which emotions they have, when they have
them, and how they experience and express these emotions.
It is broadly defined as a set of processes used by people to manage all emotional states
including broad affects, moods, specific emotions, and stress (Koole, 2009). Emotion regulation
is described in terms of targets and functions. Primary targets of emotion regulation are attention,
relevant cognitive-emotion knowledge and bodily emotional manifestations. It seeks to meet
psychological functions such as the satisfaction of hedonic needs, furthering goal pursuits, and
facilitation of the global personality system (Gross & Thompson, 2009). Combining the previous
definitions, a construct emerges that involves both positive and negatively-valenced emotions,
and the processes that may serve to enhance, suppress, and sustain them, or even to replace them
with other emotions (Butler & Gross, 2004).
So emotionregulation may be automatic or controlled, conscious orunconscious, and may
involve the up or down-regulation(i.e., increase or decrease) of various aspects of negative
orpositive emotions (Parrott 1993). Cole, Michel and Teti (1994) posited that regulation of
emotion is the ability to respond to the ongoing demands of experience with the range of
emotions in a manner that is socially tolerable and sufficiently flexible to permit spontaneous
reactions as well as the ability to delay spontaneous reactions as needed.
Emotion regulation (ER) involves awareness, understanding, and acceptance of emotions,
the ability to control impulsive behaviors related to negative emotions, and the ability to use
flexible emotions in order to meet individual goals and situational demands. The absence of any
of these components would signify the presence of difficulties in emotion regulation, (otherwise
known as emotion dysregulation, ED) (Gratz & Roemer, 2004). As such, these dysregulated
processes may not be optimal in meeting long-term goals and environmental demands (e.g.,
under- regulation or insufficient regulation of the amount and intensity of expressed emotion,
and over-regulation).
Emotion dysregulation has been defined as difficulties in controlling the influence of
emotional arousal on the organization and quality of thoughts, actions, and interactions.
Individuals who are emotionally dysregulated exhibit patterns of responding in which there is a
mismatch between their goals, responses, and/or modes of expression, and the demands of the
social environment (Zeman, Cassano, Perry-Parrish & Stegall, 2006).According to Beauchaine,
Gatzke-Kopp and Mead (2007), emotion dysregulation refers to an emotional response that is
poorly modulated, and does not fall within the conventionally accepted range of emotive
response. It may be referred to as labile mood (marked fluctuation of mood or mood swings).
People vary significantly in the quality and intensity of their emotional responding to similar
stimuli and situations (Davidson 1998).
According to Gross (2015), the terms ‘emotion regulation’ and ‘emotion dysregulation’
refer to processes by which individuals change or maintain the intensity or the valence of an
emotional experience in order to appropriately respond to environmental demands. The
regulation of emotions may be conscious/overt or non-conscious/covert. The ability to adaptively
regulate emotions is crucial for healthy functioning. Both negative and positive emotions may be
regulated. Over the years many authors have focused mostly on strategies used to influence and
modify negative emotions. In fact, negative emotions and dysregulation of negative affect have
been shown to be related to psychopathology (Aldao, et al., 2010; Aldao & Nolen-Hoeksema,
Moreover, different theoretical models have highlighted different specific strategies that
are adaptive or maladaptive, and the latter has been correlated with different types of disorders.
Maladaptive strategies which are generally considered to be associated with negative outcome
are: avoidance, rumination and suppression (namely the suppression of the emotional display or
of the emotional experience), whereas adaptive strategies are problem solving, acceptance and
reappraisal (Aldao, et al., 2010).
Possible manifestations of emotional dysregulation include affective or emotional
instability, intense efforts to avoid real or perceived abandonment, unstable interpersonal
relationships, angry outbursts or behavior outbursts such as destroying or throwing objects,
aggression towards self or others, crying, accusing, creation of chaos or conflict, and threats to
kill oneself. These variations usually occur in seconds to minutes or hours. Nonetheless, most of
the extant scientific literature addressed the relationship between the use of maladaptive
strategies evidencing that their use is associated to psychopathological disorders such as
depression (Ehring, Tuschen-Caffier, Schnülle, Fischer & Gross, 2010; Joormann & Gotlib,
2010; Brockmeyer, Bents, Holtforth, Pfeiffer & Herzog, 2012; Berking, Wirtz, Svaldi &
Hofmann, 2014), anxiety, (Aldao, et al., 2010; Aldao & Nolen-Hoeksema, 2012) and other
mental disorders (Berking & Wupperman, 2012). However, results suggest that difficulties in
emotion regulation may be markers of cognitive impairment in other psychological diseases (Gul
& Ahmad, 2014).Studies(Baglioni, Spiegelhalder, Lombardo & Riemann, 2010; Mauss, Troy &
LeBourgeois, 2013; Sandru & Voinescu, 2014; Tsypes, Aldao & Mennin, 2015) found that
emotion regulation has been associated with self-reported poor sleep quality. This effect could
have important consequences for individual’s healthy functioning as poor sleep may affect
mental health both directly and indirectly as a mediating factor.
It is also possible that the personality traits of an individual will determine one’s sleep
quality.Personality traits are aggregate characteristics and qualities displayed by an individual
over time and across different situations. It is believed that individual differences in
psychological distress and mental health are partly rooted in personality characteristics
(Friedman, 1990), and among the primary dimensions of personality, neuroticism is the chief
determinant of mental health outcomes (Watson & Clark, 1984).
Neuroticism (negative emotionality, trait anxiety, negative affectivity) is a personality
trait, or emotional disposition used in personality research as a gauge of emotional stability
(Lahey, 2009). It is a construct which has been defined in numerous ways. Some researchers
have defined neuroticism as the tendency to experience negative distressing emotions and
physical symptoms (Merkelbach, König & Sittinger, 2003), the general disposition to develop
psychopathological symptoms such as anger, anxiety and depression as it is sometimes called
emotional instability (Jeronimus, Riese,Sanderman & Ormel, 2014), negative affect (Wilson &
Gullone, 1999), and a psychological tendency to perceive threat (Schneider, 2004). Costa and
McCrae (1992) defined neuroticism as a dimension of maladjustment or negative emotionality
versus adjustment and emotional stability. Differences among definitions have been reconciled in
the late 1990s with the consensus definition that, at its core, neuroticism is the propensity to
experience negative emotions (Widiger, 2009). Mathew and Deary (1998) maintain that a
neurotic person has an enduring tendency to experience negative emotional states and feeling
such as guilt, envy, anger, anxiety and depressed mood.
Neuroticism is defined as the proneness of the individual to experience negative affective
states, and may also be associated with increased exposure to stressful life events (Bolger &
Zuckerman, 1995),and greater susceptibility to the adverse effects of stress (Ormel, Oldehinkel
& Brilman, 2001; Kendler, Kuhn & Prescott, 2004) The correlates of this trait are profound
including low subjective well-being, perceptions of low physical health, maladaptive reactions to
illness, higher levels of psychopathology, less mature levels of identity achievement and a lower
quality of social and romantic relationships (Ozer & Benet-Martı´nez, 2006).
Eysenck and Eysenck’s (1964, 1975, 1985) personality proposition considers neuroticism
as one of the three central behavioural attributes which is found in various degrees in a normal
population. In Eysenck’s view, neuroticism is based on activation thresholds in the sympathetic
nervous system or visceral brain.Another way of thinking of neuroticism is as a negative
emotional reactivity continuum ranging from low to high. For instance, a person high in
neuroticism may have strong negative reactions in the response to threats, frustration, or loss,
while someone low in neuroticism may just brush it off. Another instance, people high in
neuroticism but within the normal range, may experience heightened neuroticism during times of
stress, (Lahey, 2009).
Neurotic people, who have low activation thresholds, and who are unable to inhibit or
control their emotional reactions, experience negative affect (fight-or-flight) in the face of very
minor stressors – they are easily nervous or upset. By implication, individuals who score high on
measures of neuroticism may be more likely to experience such feelings as anxiety, anger, envy,
hostility, guilt and depressed mood. They may be prone to interpreting ordinary situations as
threatening and minor frustrations as hopelessly difficult; often self-conscious and shy, and may
have trouble with self-regulation. Generally, neuroticism reflects individual differences in
behaviour which are thought to be pervasive across different situations. Researchers (Eysenck &
Eysenck, 1985; Eid & Diener, 1999) have also observed that neuroticism is associated with more
variability in behaviour and experience. Consequently, it is important to consider the role of
individual, developmental and social factors in neuroticism because of neuroticism’s significance
as a risk factor in psychopathology (Costa & McCrae, 1980; Malouff, Thorsteinsson & Schutte,
2005; Griffith, Zinbarg, Craske, Mineka, Rose, Waters & Sutton, 2009).Neuroticism is related to
and a robust predictor of many mental and physical health problems, (Lahey, 2009).
The public health and educational relevance of neuroticism have also been demonstrated
by studies on the personality-psychopathology association within a network of traits and
symptoms (Gainey, 2011; Lahey, 2012, Magee, Patrick & Leonie, 2012). Specifically, high
levels of neuroticism have been found to be associated with higher risk of major depression
(Fanous, Neale, Aggen & Kendler, 2007), increased risks of psychiatric morbidity among
individuals with anxiety and mood disorders (Griffith, et al., 2009), memory problems (Neupert,
Mroczek & Spiro, 2008) and poor problem solving (Owen, 2007). A relatively recent study
(Cuijpers, Smit, Penninx, de Graaf, ten Have & Beekman, 2010) indicated that the economic
costs of neuroticism are more than the costs of mental and physical illnesses not only because
neuroticism is associated with those disorders but also due to its contributions to general
Research has revealed some relations between neuroticism and sleep indicating that
neuroticism and self-criticism were negatively related to sleep length, even after controlling for
depression and anxiety (Vincent, Cox & Clara, 2009).Recent studies (Soehner, Kennedy &
Monk, 2007; Calkins, Hearon, Capozzoli & Otto, 2013;Duggan, Friedman, McDevitt &
Mednick, 2014) reported that high neuroticism were the best predictors of poor sleep (i.e., poor
sleep hygiene, low sleep quality, and increased sleepiness). However, there is little research of
sizable samples to identify neuroticism traits are related with sleep quality in adults particularly
university graduate students. There is a need to assess the relationship between sleep quality and
neuroticism for effective preventive mental health interventions in graduate students.
Statement of the Problem
Sleep quality and its consequences is asignificant public health issue – an issue that has
caused health organizations investing a lot of money into sleep education (Sateia & Nowell,
2004).Of the various psychological contributing factors to poor sleep quality, dysfunctional
thoughts and beliefs have been researched in recent times. Morin (1993) postulated that how one
thinks about his/her sleep is likely to contribute to one’s ability to initiate and maintain sleep. It
is an important indicator of adults’ health and well-being (Tynjälä, Kannas, Levälahti &
Välimaa, 1999). Good sleep quality is associated with a wide range of positive outcomes such as
better health, less daytime sleepiness, greater well-being and better psychological
functioning,while poor sleep quality is one of the defining features of chronic insomnia
(Edinger, Bonnet & Bootzin, 2004). Good sleep quality and adequate amount of sleep are
important in order to have better cognitive performance and avoid health problems and
psychological disorders.
Lack of sleep has been found to have significant effects on concentration, memory, and
other neuropsychological deficits (Sadock & Sadock, 2005), physical health and well-being
(Nunes, Jean-Louis, Zizi, Casimir, Gizycki & Brown, 2008), as well as psychological health
(Hamilton, Nelson, Stevens & Kitzman, 2007). Sleep problems have been the subject of
empirical inquiry by researchers for decades and the most common problems investigated
include delay of sleep onset, difficulty staying asleep, awakening too early, as well as inadequate
quantity and quality of sleep (Mendelson, 1987). Numerous studies have been conducted (e.g.
Ellis, Hampson& Cropley, 2007; LeBourgeois, Giannotti, Cortes & Wolfson, 2005; Paine,
Gander, Harris & Reid, 2005) to unravel the etiological complexities of sleep quality in an
attempt to search for effective prevention programme. However, it is evident from studies done
that varieties of factors prevent a good quality of sleep in our society, particularly in Nigeria,
(Odetola &Adejumo, 2014).
Poor sleep quality is a distressing consequences of trauma exposure. Some of these
include loss of loved ones, divorce, severe accident, physical and sexual abuse, emotional and
physical neglect, loss of property, terminal illness, exposure to war, domestic violence and
personality trait.Given that sleep disturbances is a common experience following trauma
exposure and may contribute to the development and maintenance of PTSD, sleep disturbances is
an important factor to investigate.
Emotion regulation may bea contributing to poor sleep quality, specifically in the form of
emotion regulation difficulties, associated with trauma exposure and PTSD symptoms through
the effects that emotional processes have on sleep onset and restfulness. Sleep problems may be
aggravated by neuroticism, predisposing people to react to life stressors with negative emotions,
thoughts, and behaviours. Heightenedneuroticism and dysregulated emotions may aggravate the
regulation of sleep and mood through catastrophic worry (Nanette, 2013).
The present research focuses on exposure to trauma, emotion regulation and neuroticism
in explaining sleep quality. Nigerian adults are too often exposed to trauma and this is becoming
a global concern. Student population group have come to be greatly affected by sleep
difficulties.The impact of sleep disorders in postgraduate students could be severe and can affect
both academic and personal activities. Most students may have gone through one traumatic event
or another in which they may become preoccupied with thoughts about their action during the
event, often experiencing guilt or shame over what they did or did not do. Some may withdraw,
subdued or even mute after a traumatic event which may cause them to have difficulty falling or
staying asleep which will later lead to performance impairment, lack of concentration, bad
behavior, and poor relationship. It is in this view that this research is being conducted with a
view to understanding students’ emotional and physical challenges.
This study is imperative because more information is needed to better understand sleep
quality and to give room for appropriate intervention. The research problems that informed this
study could be stated as follows: (a) need assessment for psychological interventions among
post-graduate students have not considered the psychosocial health of the graduate students, (b)
there is dearth of empirical knowledge on the unique individual contributions of trauma exposure
on sleep quality among postgraduate students, (c) the insufficient understanding of the role
played by emotion regulation and neuroticism on sleep quality.
Thus, the present study specifically sought to provide answers to the following questions:
1. Will trauma exposure predict sleep quality among postgraduate students?
2. Will emotion regulation predict sleep quality among postgraduate students?
3. Will neuroticism predict sleep quality among postgraduate students?
Purpose of the Study
Aloba, Adewuya, Ola and Mapayi (2007) acknowledged that the extent of sleep-related
problems remains largely an unidentified public health issue, particularly so in Africa where
there is inadequate personnel to assess sleep problem. Studies focusing research investigation on
the variables under study are lacking. This study is therefore aimed at investigatingwhether
trauma exposure,emotion regulation and neuroticismwill significantly predictsleep quality
among postgraduate students.
Operational Definition of Terms
Sleep Quality:Thisrefers to quantitative (i.e., sleep duration, sleep latency, sleep maintenance,
number of arousals) and subjective aspects (i.e., depth, restfulness) of sleep and refreshment
upon awakening as measured by Pittsburgh Sleep Quality Index (Buysse, Reynolds, Monk,
Berman & Kupfer, 1989).
Trauma Exposure:TraumaExposure is a traumatic event which includes individuals either
experiencing or witnessing an event during which they experienced intense fear, helplessness, or
horror, as measured by part A of Harvard Trauma Questionnaire (Mollica, Caspi-Yavin, Bollini,
Truong, Tor & Lavelle, 1992).
Emotion Regulation: This refers to the person’s manner of influencing which emotions he/she
has, when he/she has them, and how these emotions are experienced and expressed, as measured
by Difficulties in Emotion Regulation Scale (Gratz & Roemer, 2004).
Neuroticism:This is operationally defined by items referring to irritability, anger, sadness,
anxiety, worry, hostility, self-consciousness and vulnerability that have been found to be
substantially correlated with one another in factor analysis as measured by Neuroticism subscale
of Big Five Inventory (John, Donahue & Kentle, 1991).
Postgraduate students: This refers to students of the University of Nigeria, Nsukka who are
enrolled in postgraduate diploma, master’s degree and PhD programmes.