Insomnia is very common in depression and especially medical students are easy to experience sleep disturbance because of their studies. Also depressive symptoms are closely related to stress. Stress is an interaction between an individual and the environment, involving subjective perception and assessment of stressors, thus constituting a highly personalized process. Different personality traits can create different levels of stress. In this study, we tried to explore the relationship between insomnia and depressive symptoms or stress of medical students, and whether their personality may play a role on this relationship or not.
We enrolled 154 medical students from University of Ulsan College of Medicine. We used the Medical Stress Scale, the Multidimensional Perfectionism Scale, the Patient Health Questionnaire-9, the Academic Motivation Scale, the Insomnia Severity Index, and The revised NEO Personality Inventory (PI).
Insomnia severity, amotivation, medical stress, mental health index and neuroticism traits of NEO-PI significantly correlated with depressive symptom severity (p < 0.001). And stepwise linear regression analysis indicated insomnia, amotivation and neuroticism traits of NEO-PI are expecting factors for students’ depressive symptoms is related to (p < 0.001).
Student who tend to be perfect feel more academic stress. The high level of depressive symptom is associated with insomnia, amotivation, academic stress in medical student. Moreover, personality trait also can influence their depressive symptoms.
Researchers have studied the condition of depression as manifest in medical students for several decades. Depressive symptoms are closely related to perceived stress. Since there are various type of stressors present during any period of formal medical training [
Medical students are also prone to sleep disturbance. Their sleep-wake cycle is frequently interrupted by delayed sleep onset and inadequate sleep duration, with secondary daytime somnolence and napping [
Previous studies showed that personality traits are associated with mood symptoms. High neuroticism was reported to be associated with major depressive disorder, and low extraversion was correlated with dysthymia in general population [
Therefore, it is important to explore whether the insomnia symptoms of medical students influences their medical stress or depressive symptoms. In this study, we tried to explore the relationship between insomnia and depressive symptoms or stress of medical students, and whether their personality may play a role on this relationship or not.
We enrolled 154 medical students ranging from the second year of pre-medicine through the third year of medical school at the University of Ulsan College of Medicine, and assessed their current academic stress and psychological problems such as sleep problem or depressive symptoms in 2015.
Before starting of the survey, we explained all details about the aims and methods of the study to the 159 students. We distributed printed questionnaires to the students, and requested that the students fill in them. Finally data of 154 students, who have consented, were included in the final analyses. The official approval of this study was authorized by the Institutional Review Board of the Asan Medical Center.
Students’ medical stress and academic motivation was assessed using the Medical Stress Scale (MSS) and Academic Motivation Scale (AMS). Their insomnia severity and depressive symptoms were checked using the Insomnia Severity Index (ISI) and Patient Health Questionnaire-9 (PHQ-9), Personality trait was assessed using the revised NEO Personality Inventory (NEO-PI) and the Multidimensional Perfectionism Scale (MPS).
The MSS is a self-report questionnaire to assess perceived stress levels in medical school [
The AMS consists of a 28-item questionnaire to assess academic motivation [
The ISI is a brief Self-Report Scale to evaluate the degree of both daytime and nighttime constituents of insomnia. The ISI consists of seven items to estimate the degree of sleep maintenance problems; sleep-onset difficulties and early morning awakening, satisfaction with his or her sleep state, influence on the functions of normal daytime life, severity of impairment of life of quality and level of concern caused by insomnia. All items have a 0–4 scale so the range of total score is from 0 to 28 (0–7: normal, 8–14: mild insomnia, 15–21: moderate insomnia, 22–28: severe insomnia) [
The PHQ-9 is an instrument about the assessment of depressive symptoms based on DSM-IV criteria. It was developed as a self-report version of the original PRIME-MD by Spitzer et al. [
The revised NEO-PI evaluates personality based on the big five model. It has 240 questions and consists of openness to experience, conscientiousness, extraversion, agreeableness and neuroticism [
The MPS is a scale to assess the perfectionistic propensity. The MPS is invented by Frost et al. [
A t-test of students has been used to make a comparison of the demographic and psychological characteristics between depressed students and non-depressed students. We also used Pearson’s correlation analysis to determine the relationship between depressive symptoms and carious other psychological variables. Based on these results, stepwise linear regression analysis has been performed to find the factor related to depressive symptoms. We used The Statistical Package for the Social Sciences version 21.0 (SPSS Inc., Chicago, IL, USA) for all statistical analyses.
In our study group, only 32 (20.7%) students were female.
We performed Pearson’s correlation analysis to find out the association between depressive symptoms and other psychological characteristics (
Next, based on these findings we have constructed stepwise linear regression model (
We proved that stress is significantly related with insomnia. We also determined that medical students who have neuroticism trait experienced more stress in medical school. Furthermore, we found that students who have high level of depressive symptoms tend to experience more insomnia and loss of motivation. Stress has a cause-and-effect relationship with depression, as shown by numerous previous studies. It became clear that chronic exposure to perceived stressors caused depression-like stress by making molecular, cellular, and behavioral changes [
Insomnia is closely linked to enrollment in medical school. There are already a proliferation of studies addressing the relationship between medical school, medical students and sleep disorders. In Asia, numerous researches were done to assess insomnia severity in medical students in China, Hong Kong, Malaysia, India, and Iran. In North and South America, United States, Brazil, and Mexico have epidemiological data on insomnia of medical students [
Prior literary sources indicate document the belief that various psychiatric disorders have higher incidence and prevalence when the afflicted individuals suffer from insomnia. Insomnia patients are about four times more likely to develop depression than those who sleep well [
Our research indicates that some personality traits are related to depressive symptoms, too. Over previous decades, many researchers published papers documenting the possible relationship between personality and psychiatric disorders. In general population, the patient diagnosed with anxiety and depressive disorders will likely have more extraversion and neuroticism traits [
Neuroticism is the propensity to experience pessimistic emotions, for example anxiety or sadness, including mood swings [
Motivation has been shown to affect the depressive symptoms in medical students. In medical school, there are various type of “stress” including “academic stress” [
There are several constraints in play in the current study. First of all, we had no means of verifying any of the participants’ self-described medical histories, especially when it came to the area of psychiatrics. If there was to be a large or disproportionate percentage of depressive disorder among our participants, it could adversely affect the raw data and the results. Second and as noted, this research is based on self-report questionnaires which contain subjective bias. However, the most of participants have experience to filling out questionnaires much like hours at some point during the last year. So they would be appropriately familiar with that process. Third, this was a cross-sectional study. So we could find the association between variables, but it was impossible to establish the causality. Forth, we didn’t accomplish the comparison about medical students and the students who have another major. In Korea, college students are in the most stressful situation including seeking a full-time job and student loan repayment. So the influence of insomnia and stress could be different to non-medical students. Furthermore there would be a personality difference between them. Further studies will be performed considering the possibilities.
The authors have no financial conflicts of interest.
Demographic and psychological characteristics of participants
Variables | Stressed (n = 55) | Non-stressed (n = 99) | p-value |
---|---|---|---|
Gender | |||
Male | 44 | 78 | |
Female | 11 | 21 | |
School year | 1.5 ± 1.1 | 1.5 ± 1.1 | 0.41 |
Motivation | |||
Amotivation | 9.3 ± 3.1 | 6.9 ± 2.4 | 0.04 |
Intrinsic motivation | 38.9 ± 7.2 | 40.5 ± 6.3 | 0.30 |
Extrinsic motivation | 43.6 ± 4.9 | 43.4 ± 5.5 | 0.68 |
ISI | 6.1 ± 4.2 | 4.0 ± 3.4 | < 0.01 |
PHQ-9 | 5.3 ± 4.5 | 2.7 ± 2.7 | 0.08 |
Perfectionism | |||
Excessive concern over making mistakes | 26.6 ± 6.5 | 22.4 ± 6.3 | 0.99 |
High personal standards | 21.4 ± 5.3 | 20.3 ± 5.1 | 0.77 |
Perception of high parental expectations | 14.8 ± 4.6 | 13.7 ± 4.5 | 0.60 |
Perception of high parental criticism | 6.6 ± 1.8 | 5.6 ± 2.1 | 0.10 |
Doubting of the quality of one’s actions | 11.6 ± 3.6 | 10.1 ± 3.0 | 0.12 |
Preference for order and organization | 18.3 ± 5.6 | 17.4 ± 5.2 | 0.48 |
NEO-PI-mental health index | 58.1 ± 12.4 | 68.0 ± 10.8 | 0.06 |
Extraversion | 43.8 ± 10.3 | 46.7 ± 9.2 | 0.56 |
Openness to experience | 47.8 ± 10.0 | 46.7 ± 8.9 | 0.61 |
Agreeableness | 41.5 ± 8.4 | 47.2 ± 10.7 | 0.15 |
Conscientiousness | 46.0 ± 9.7 | 47.3 ± 8.3 | 0.27 |
Neuroticism | 53.4 ± 8.4 | 46.5 ± 6.3 | < 0.01 |
‘Stressed’ students had Medical Stress Scale scores ≥ 28 and ‘non-stressed’ students had MSS scores < 28. ‘School year’ was re-coded as follows; 0: the second year of pre-medicine, 1: the first year of medicine, 2: the second year of medicine, 3: the third year of medicine.
ISI: Insomnia Severity Index, PHQ-9: Patient Health Questionnaire-9, NEO-PI: NEO Personality Inventory, MSS: Medical Stress Scale.
Correlation of depressive symptoms with psychological characteristics
Variables | Pearson’s R2 | p-value |
---|---|---|
Motivation | ||
Amotivation | 0.30 | < 0.01 |
Intrinsic motivation | -0.19 | 0.02 |
Extrinsic motivation | -0.12 | 0.15 |
ISI | 0.31 | < 0.01 |
MSS | 0.31 | < 0.01 |
Perfectionism | ||
Excessive concern over making mistakes | 0.25 | 0.002 |
High personal standards | 0.01 | 0.92 |
Perception of high parental expectations | 0.09 | 0.30 |
Perception of high parental criticism | 0.16 | 0.04 |
Doubting of the quality of one’s actions | 0.20 | 0.01 |
Preference for order and organization | -0.08 | 0.30 |
NEO-PI-mental health index | -0.40 | < 0.01 |
Extraversion | -0.15 | 0.07 |
Openness to experience | 0.02 | 0.78 |
Agreeableness | -0.26 | 0.001 |
Conscientiousness | -0.17 | 0.04 |
Neuroticism | 0.42 | < 0.01 |
NEO-PI: NEO Personality Inventory, ISI: Insomnia Severity Index, MSS: Medical Stress Scale.
Result of stepwise linear regression (B) for expecting depressive symptoms measured using PHQ-9
Outcome variables | Explanatory variables | β | B | p-value |
---|---|---|---|---|
PHQ-9 (R2 = 0.455, p < 0.001) | ISI | 0.39 | 0.37 | < 0.01 |
Amotivation | 0.22 | 0.28 | < 0.01 | |
Neuroticism | 0.34 | 0.16 | < 0.01 |
ISI: Insomnia Severity Index, PHQ-9: Patient Health Questionnaire-9.