Report on Sleep Quality, Age and Depression in PSY3062 Course

This report, prepared for a PSY3062 course, investigates the relationship between sleep quality, age, and depression, focusing on a late-onset age group (34-84 years old) in the United States. The study, using a correlational design, examined 1168 valid questionnaires from participants who completed the MIDUS II Project phone interview, using the Center for Epidemiological Studies Depression Inventory (CES-D) to measure depression and the Pittsburgh Sleep Questionnaire (PSQ) to assess sleep quality. The research hypothesized that better sleep quality correlates with lower depression levels, moderated by age. The results, analyzed with ANOVA, revealed significant main effects for gender and sleep quality, with girls showing more depression symptoms and higher sleep quality correlating with lower depression. The study underscores the complex interplay between sleep, age, and mental health, highlighting the need for further research to understand these relationships fully and improve interventions.

Running head: SLEEP QUALITY, AGE AND DEPRESSION 1
Topic: How does Sleep Quality and Age affect Depression?
[University]
Bryan Chye Zhang Terng
28379268
Submitted as PSY3062 Milestone 1
Tutor: Mrs. Goh Pei Hwa
Class: MA_Clab06_9403
Word Count: 1500 words

SLEEP QUALITY, AGE AND DEPRESSION 2
Contents
Introduction......................................................................................................................................3
Sleep Quality vs Depression........................................................................................................4
Age vs Depression........................................................................................................................5
Current Study...............................................................................................................................6
Methods...........................................................................................................................................6
Participants..................................................................................................................................6
Design of the Study......................................................................................................................7
Measure........................................................................................................................................7
Center for Epidemiological Studies Depression Inventory (CES-D)...........................................7
Pittsburgh Sleep Questionnaire (PSQ)........................................................................................8
Data Analysis Plan.......................................................................................................................8

SLEEP QUALITY, AGE AND DEPRESSION 3
Ethical Issues...............................................................................................................................9
Hypotheses.......................................................................................................................................9
Conceptual Model/ Framework.......................................................................................................9
Results............................................................................................................................................10
Quality of sleep, Age differences and depression.........................................................................11
Quality of sleep, gender difference and depression.......................................................................12
Sleep duration, depression.............................................................................................................13
Discussion......................................................................................................................................14
Limitations.....................................................................................................................................15
Future Research.............................................................................................................................16
Conclusion.....................................................................................................................................17
References......................................................................................................................................18
Appendix........................................................................................................................................24
Introduction
Depression has always been a main issue among all individuals throughout the 21st century. It is
one of the major causes that lead individuals to have suicidal thoughts, addiction to drugs, self-
injury and reckless behaviour. It does not only affect individuals’ mental state, but also
influences the quality of life and increasing the risk to acquire diseases such as cardiovascular
diseases, diabetes, stroke and obesity. Countless research examined the relationship between
sleep quality and depression, and age with depression separately, with debates going on about
determining sleep quality or depression as a causation to each other. But these researches did not
consider both of the factors together. Therefore, this paper aimed to determine the relationship
between sleep quality, age and depression.
Sleep Quality vs Depression
Sleep quality is an important determinant for a good physical and mental health. Hayashino
(2010) and her team found out that comorbid conditions is highly associated with depression and

SLEEP QUALITY, AGE AND DEPRESSION 4
sleep via a population-based survey. Le Blanc et al. (2007) discovered a correlation between low
quality of life, sleeping problems such as insomnia and having depression at the same time.
Another research conducted by Demirci and team (2015) found out that sleep quality and
depression affect each other in a two-way relationship via their experiment of determining the
consequence of using smartphone among university students. Sleep problems such as insomnia
and hypersomnia can lead to lower productivity at work, which causes workers to not perform
well due to the experience of depression which lead them complete their task unsuccessfully
(Nutt, Wilson, & Paterson, 2008).
On the other hand, depression can also be a determinant for sleep quality. In a sample of 500
high school students in Japan, children and adolescents which experienced poor mental health
conditions reported to have sleep disturbances in their daily lives (Kaneita et al., 2009). Whereas
among depressive patients in a hospital in UK, three quarters of them reported difficulties in
waking up and falling asleep in their daily routine (Yates et al. 2007). Disturbed sleep may lead
to a lower quality of life in individuals. Chen, Burley, & Gotlib (2012) conducted a research on
44 girls with/without depression, and girls with higher risk of depression reported having more
sleeping difficulties. However, this research has its weakness. As girls with high-depression risk
may have a negative perception towards their sleep difficulties, they may or may not have severe
sleep disturbances at all. Thus, they might be bias in their reports. Nevertheless, many researches
still manage to establish a correlation between sleep quality and depression.
Age vs Depression
Age is a moderating variable for depression risk in a person. Depression is categorized as an
equal-opportunity mood disorder that can to begin at any age. This disorder can be divided into
two categories, which is early-onset and late-onset. Early-onset involves observing depression
among children, adolescents and young adults where as late onset involves adults which age
from 65 years old and above. ADAA (Anxiety and Depression Association of America) reported
that 2 to 3 percent among children between 6 and 12 years old experiences serious depression.
Whereas in year 2014, 6 to 8 percent (2.8 million) adolescents aged between 12 to 17 years old
experienced at least one major depressive episode throughout their schooling life (Yeh & Chiao,
2016). Young adults aged from 18 to 22 years old are one of the most vulnerable groups to have

SLEEP QUALITY, AGE AND DEPRESSION 5
suicidal thoughts due to depression. In 2016, 13.15 percent of young adults who experienced
major depressive episodes committed suicide.
Adults and the Elderly (>65 years old) are age groups which reported to have acquire major
depressive disorder at the highest rate (O’Neil, 2007). Adults hold responsibilities financially,
important roles to play within a family, which acts as a ‘backbone’ to a family structure, which
made work stress the major cause of depression among adults (Melchior et al., 2007). Whereas in
the elderly, statistics indicated the depression rate is highest in this group. In America alone, 6.5
million out of 35 million elderly (18.14%) acquires depression due to many reasons, such as life
expectancy, lost of friends, having physical illness and has limited financial resources (Huen and
Hein, 2005). Consequences for not treating depression in this age group are obtaining chronic
diseases, having suicidal thoughts along with memory decline (Vink, Aartsen, & Schoevers,
2008).
One common problem faced by all age groups with depression is the inability to manage stress
(Hammen, 2005). But age is not a major contributor to depression, but rather just a phase in life
where different kinds of problems will hit respective age groups. Therefore, more research that
links other factors and age to depression has to be conducted.
Current Study
The aim of this paper is to determine the impact of both sleep quality and age on depression
among late-onset age groups (34-84 years-old) in the United States. It is hypothesized that
people with better qualities of sleep has a lower level of depression, and the relationship is
moderated by age, which different life stages yields different results.
Methods
Participants
One thousand two hundred and fifty-five participants were involved in the research. Participants
are eligible to the research if they completed the MIDUS II Project 1 phone interview and self-
administered questionnaire, were in the MAINRDD and are living in the continental of the
United States. However, only 1172 questionnaires were completed, and 1168 of them are valid.
Participants are comprised of 505 males and 663 females, with an age range from 34-84 years
old, with a mean age of 54.49. The recruitment of participants is a two-step process.

SLEEP QUALITY, AGE AND DEPRESSION 6
First, recruitment packets will be distributed to households at designated data collection sites by
the staff, and participants will be assigned to one of the data collection spots: UCLA, University
of Wisconsin or Georgetown University. Next, participants will be contacted by research staff on
questions they have about the questionnaire and to facilitate an interview with individuals that
acquire major depression and has sleeping problems. Verbal and written consent were given to
participants for the conduct of an interview, and it is approved by the Health Science Institutional
Review Boards and all the other authorities involved.
Design of the Study
This will be a correlational design. The subject variable for the research is sleep quality, and the
score for Pittsburgh Sleep Questionnaire were recorded. The moderating variable is the age of
participants. Whereas the dependent variable of the research is depression score, which is
determined by the Center for Epidemiological Studies Depression Inventory (CES-D). So, this
research examines how sleep quality affects depression with age as a moderating variable.
Measure
Participants are required to fill in a self-administered questionnaire (SAQ) which consists of two
components. This included the Center for Epidemiological Studies Depression Inventory (CES-
D) and Pittsburgh Sleep Questionnaire (PSQ).
Center for Epidemiological Studies Depression Inventory (CES-D)
This inventory consists of 20 items and 8 subscales. The 8 subscales measures sadness, loss of
interest, appetite, sleep, thinking, guilt, tired, movement, and suicidal ideation respectively.
Participants are required to rate their score from a scale of 0 (rarely or none of the time) to 3
(most or all of the time). The total score to be obtained ranges from 0 to 60. 4 items of the
questionnaire were remarked with “R” which will be reverse-coded so that higher scores can
reflect higher standing in the scale.
Scale scores were computed by summing across all items for which there were no missing data.
A higher score indicates a higher depression score whereas a lower score indicates a healthier
mental state. The CES-D inventory has a high internal consistency. The validity and reliability
has also been found similar to the general population.

SLEEP QUALITY, AGE AND DEPRESSION 7
Pittsburgh Sleep Questionnaire (PSQ)
This questionnaire is a two-paged document which consists of seven components, which are
subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep
disturbance, use of sleep medication and daytime dysfunction respectively. Some questions are
to be answered by the participant’s bed partner or sleep mate. The summation of scores form the
global sleep quality score. PSQ scores were used to determine sleep quality as they have a high
reliability and validity.
Data Analysis Plan
IBM SPSS 24 was used to compute all the data. Descriptive statistics analysis will be performed
to obtain basic information such as the total number of participants involved (N), maximum and
minimum value, mean (M) and standard deviation (SD).
Next, Shapiro-wilk’s test will be performed to test the normality of the data, reduce the skewness
and remove outliers, which all data that exceeds the significant value of (p < .05) will be
considered as violating the assumption. But due to the large sample size (N = 1255), the central
limit theorem could also be applied to remove outliers, that is if the assumption of normality is
violated. A z-score is also used to test the presence of outliers.
The primary analysis for this research is multiple linear regression, and the p-value threshold for
a significant data will be α = .05.
Ethical Issues
The participants together with any concerned party were informed about the study, the
intervention and the type of questions that the participants would be asked during the interview.
The participants and their guardians were to issue their written approval of their participation
prior to the intervention in the study. All the data collected during the study were approved by
the review committee.
Hypotheses
Given the above, in this study, the null and alternative hypotheses to be tested can be formulated
as;
H0: Sleep quality affects depression

SLEEP QUALITY, AGE AND DEPRESSION 8
Against
H1: Sleep quality does not affect depression
And
H0: Age affects the depression
Against
H1: Age affects the depression
Conceptual Model/ Framework
Independent variable – Depression
Dependent variables - Sleep Quality and Age
Results
This study examined the relationship between the quality of sleep and symptoms of
depression and anxiety and whether this relationship varied with gender. Four fixed factor
ANOVAs were conducted to analyze the data for depression and anxiety separately, the
Depression
(Independent Variable)
Sleep Quality
(Dependent variable)
Age
(Dependent Variable)

SLEEP QUALITY, AGE AND DEPRESSION 9
factors being sleep quality/duration (high vs. low) x gender (boys vs. girls). The alpha
criterion for significance was set at .05. Table 1 shows descriptive statistics for all variables.
Table 1.
Descriptive statistic
Mean Std.
Deviation
Range
Sleep Duration Boy
Girl
6.9
7.1
1.3
1.0
8.0
6.5
Total 7.0 1.1 7.2
Quality of Sleep Boy
Girl
LSQ
HSQ
LSQ
HSQ
2.91
1.63
2.83
1.59
0.60
0.21
0.23
0.23
1
1
1
1
Total LSQ
HSQ
1.60
1.61
0.50
0.49
1
1
Depression Boy
Girl
1.44
1.81
0.50
0.80
2
3.2
Total 1.12 0.65 2.6
Quality of sleep, Age differences and depression
The results from the two-way ANOVA for depression showed a significant main effect for the
gender F (1,130) = 20.484, p =.001, Partial Eta Squared = .136. Girls (M = 1.88) showed more
symptoms of depression than boys (M = 1.46). The results showed a significant main effect of
quality of sleep F (1,130) = 71.547, p =.001, Partial Eta Squared = .355 and showed a significant

SLEEP QUALITY, AGE AND DEPRESSION 10
interaction between the variables quality of sleep and gender F (1,130) = 9.846, p =.002, Partial
Eta Squared = .070. As can be seen in Figure 1, both boys and girls show more symptoms of
depression with low quality of sleep compared to high quality of sleep but this difference was
bigger for girls.
Quality of Sleep
Figure 2. Two-way ANOVA between QOS and gender and the variation with depression
Quality of sleep, gender difference and depression
The results from the two-way ANOVA for depression showed a significant main effect for the
gender F (1,130) = 13.828. p =.001, Partial Eta Squared = .096. Girls (M=1.81) showed more
symptoms of anxiety than boys (M=1.33), as shown in figure 2.
The results for the two-way ANOVA for anxiety showed a significant main effect for quality of
sleep F (1,130) = 15.402, p =.001, Partial Eta Squared = .106. And showed significant
interaction between the variables quality of sleep and gender F (1,130) = 10.957, p =.001, Partial
Eta Squared = .078.
21,1
,8137,1
2 63,
0
0,5
1
5,1
2
5,2
3
High Low
Depression
Boy
Girl

SLEEP QUALITY, AGE AND DEPRESSION 11
Quality of Sleep
Figure 2. Two-way ANOVA between QOS and gender and the variation with anxiety
Sleep duration, depression
When looking at sleep duration the results from the two-way ANOVA for depression
showed a significant main effect for gender F (1,187) = 12.740, p =.001. The results did not
show a significant main effect for sleep duration F (15,187) = 1.619, p =.072, but a
reasonably strong effect size, Partial Eta Squared = .115. The results did not show significant
interaction between the variables sleep duration and gender F (8,187) = .827, p =.580, Partial
Eta Squared = .034. The results from the two-way ANOVA for anxiety showed a significant
main effect for the gender F (1,187) = 9.604, p =.002. The results did not show a significant
main effect for sleep duration F (15,187) = 1.053, p =.403, Partial Eta Squared = .078. The
results did not show significant interaction between the variables sleep duration and gender F
(8,187) = .817, p =.589, and weak Partial Eta Squared = .034.
Discussion
The objective of this study was to examine how sleep quality and age affects depression among
people. Almost all the participants in this study responded to the questions presented to them.
The findings/results of this study are supported by the hypotheses that depression is affected by
sle This study examined the relationship between the quality of sleep and symptoms of
depression and anxiety and whether this relationship varies with gender. The study also
1 29,
,381
,351
48,2
0
0 ,5
1
,1 5
2
5,2
3
High Low
Anxiety
Boy
Girl

SLEEP QUALITY, AGE AND DEPRESSION 12
examined the relationship between sleep duration and symptoms of depression and anxiety and
whether it varies with gender as well.
Previous studies had emphasized on sleep duration to explain and evaluate the quality of sleep
(Wolfson & Carskadon, 1998). Other studies have used scales (Buysse et al., 1989) and sleep
duration measures to examine adolescents quality of sleep, but few studies have examined these
factors separately (Pilcher et al. , 1997). Previous studies on gender difference and well-being
have shown that girls, regardless of sleep habits, are more distressed than boys at this age
(Cyranowski et al. , 2000b; Greca & Lopez, 1998; Piccinelli & Wilkinson, 2000).
The results from the analyses of variance in this study consisted of two separate factors, quality
of sleep and sleep duration. The results were consistent with the previous studies regarding the
quality of sleep and the relationship with depression and anxiety (Pilcher et al., 1997). Poor
subjective quality of sleep resulted in increased symptoms of depression and anxiety among the
adolescents. The girls showed more symptoms of depression and anxiety when confronted with
low quality of sleep in this study (Greca & Lopez, 1998). Girls showed more symptoms of
depression and anxiety overall, when subjective quality of sleep was high or low.
The results from the analyses of variance for sleep duration was unexpected. The results showed
no relation between sleep duration among adolescents and increased symptoms of depression and
anxiety which indicates that sleep duration and quality of sleep are two separate factors. These
results emphasize the importance of including the quality of sleep as an independent factor when
studying the relation between sleep habits and mental health. The main limitations of this study
was that the number of girls in the sample was significantly higher than the number of boys
which could decrease the results accuracy.
Self-reports were used as a measurement for sleep duration, the quality of sleep (Yi et al., 2006)
as well as symptoms of depression and anxiety (Derogatis et al., 2010). It is the participant’s
responsibility to value and assess how their mental health and sleep habits have been for the last
three weeks. Although, self-reports have proven to be valid and reliable way to measure well-
being and behavior (Howard, 1994).
Despite these limitations the study increased the level of knowledge regarding the effectiveness
of quality of sleep as this measurement seems to work independently from sleep duration. Even
though the sample contained higher percentage of girls than boys, the sample was large which
makes the total results, regardless of gender more reliable. ep quality and age.