| Significance of the studyDepression is one of the most prevalent mental illnesses among university students. Domestic and international literature revealed that more than half population who committed suicide was suffering from depression. Early diagnosis of depression is of great importance in mental health and suicide prevention of university students. Presently, the tools assessing depression target at adult patients with depression, whose life experience greatly differs from that of university students, with reading and studying as their main life experience. Due to the close association between depression and life experience, the commonly used assessing tools for depression targeting at adult patients have poor sensitivity and specificity for university students. Therefore, in the present study, we intended to establish a depression assessing scale adapted to university students as a screening tool for the early identification of depression in university students. Therefore, an effective and practical tool can be provided for further attempts in increasing mental health of university students, preventing them from committing suicide and decreasing the suicide occurrence.Objective of the studyBased on the previous studies, we made an intensive analysis of the extensively applied depression scales. By integration of the characteristic life experience of university students, we defined the item pool for the construction of the depression scale specific for university students. By experts consulting and item analyzing, we selected the items from the pool to establish a preliminary version for pretest. The pretest survey data were statistically analyzed for the modification and improvement of the scale. After the application study, the scale was finally established. The occurrence of depression in Chinese university students, the factors contributing to depression as well as the scale norm was finally established.Subjects and methods of the study1. Construction of scale items pool1.1 Open surveyBy the field focus team and brain storming, a total of 68 sophomores from a medical university of China was randomly selected, including 26 males and 42 females with an average age of 20±1 years. They were asked to list their inner thinking and behaviors when they felt depressed. And all of these manifestations were asked to list in the order of severity. After that, the list was discussed within teams with each team having 6 team members for a final list of items stating the depression manifestations in the order of severity. The discussed list was extended into the preliminary scale items pool.1.2 In-depth interviewWe in-depth interviewed 10 university students suffering from depression, including 4 males and 6 females. In them,5 were freshmen and 5 were sophomores with an average age of 20±1 years. They were asked about their manifestations in cognition, affect, behaviors and somatization.1.3 Experts team discussionTeachers with previous and/or present work experiences in hospital psychiatry department and present job in mental counseling center of universities over 5 years constituted the experts team. The 5 experts team revised and modified the items in the pool item by item to construct a final depression symptoms items pool of university students.2. Formulation of the preliminary scale, its test and revision, and establishment of the final-versionThe research methods include Delphi experts consultation, cross-sectional survey, items analysis, exploratory factor analysis, confirmatory factor analysis and ROC curve.2.1 Subjects for Delphi expert consultationThe Delphi expert consultation was performed in 30 experts who were psychiatrist or from mental health counseling center of universities. The experts include 13 males and 17 females with their ages ranging from 33 years to 63 years and an average of 47.37±7.80 years. There were 5 Ph. D degree holders,13 master degree holders and 12 bachelor degree holders. Concerning their professional titles, there were 14 professors or chief physicians,10 associate professors or deputy chief physicians and 6 lecturers or physicians. Concerning their job experience, there were 11 in the field of mental health,12 in mental health counseling and 7 in psychiatry for 8-35 years, with an average of 19.80±7.03 years.2.2 Subjects of the first surveyFor sampling convenience, respective 2 classes from juniors and seniors of a medical university were selected for the first survey. A total of 265 university students were recruited, with an average age of 21±1 years, including 77 (29.1%) males and 188 females (70.9%).2.3 Subjects of the second surveySamples were collected nationwide, with 989 recovered questionnaires. There were 890 effective questionnaires, with an effective rate of 90.0%. The subjects aged from 16 to 25 years, with an average of 20±2 years, including 400 males (44.9%) and 490 females (55.1%).2.4 Subjects of the third surveyFor sampling convenience,3508 freshmen from a medical university were recruited for the third survey using the scale. The subjects were aged 16-24 years with an average of 20±1 years, including 1321 males (37.66%) and 2187 females (62.34%). In them,372 subjects were randomly selected for clinical interview and a second questionnaire survey.2.5 Subjects of the fourth surveyStratified randomized sampling method was used to select subjects nationwide, with 8602 recovered questionnaires. There were 340 invalid questionnaires and 8262 valid questionnaires, with an effective rate of 96.05%. The subjects were aged 16-27 years, with an average of 21±1 years, including 3061 males (38.70%) and 5065 females (61.3%).3. Research tools for factors influencing occurrence of depression in university studentsThe research tools were divided into 2 parts.The first part was a general survey, including 4 sections of demographic factors, personal factors, family factors and illness history of the subjects and their relatives. The demographic factors included gender, nationality, grade, the only child of the family, fresh graduate from high school, science or arts major, resident place of the family; the personal factors included being in love, sexual orientation, experience of sexual abuse, religion, political belief, beliefs in the next life, experience of mental health counseling. The family factors include marital status of the parents, the birth sequence of the subject, core family, educational background of the father and mother, economic income of the family, part-job or full-time job taken by parents, contact frequency with parents. The illness history of the subjects and their family member include physical illness of the subject, mental illness of the subject, mental illness of family members, death of the family members from suicide, death of acquaintance from suicide.The second part was consisted of 8 questionnaires, namely USDS, SDS, C-MLQ, SES, ASLEC, EMBU, Moderation thinking scale, Family care inventory, and Social support rating scale.Results of the study1. By literature review, open survey, in-depth interview and experts discussion, the items pool was established for depression scale of university students, including 133 indicators and 5 dimensions of cognition, affect, beliefs and behaviors, somatization and academic performance.2. Delphi Consultation to 30 experts and questionnaire survey for 265 university students were used to screen the total 133 items of depression indicators in university students. The 59 items were kept and 74 items were deleted. According to the experts suggestion,2 items were added to form the preliminary depression scale for university students. The preliminary scale was consisted of 61 items.3. After consultation to 18 experts,890 university students nationwide were tested with the scale. By second round of Delphi experts consultation and exploratory factor analysis, the items in preliminary scale were screened and the structure of the scale was explored. The test scale was established, with 30 items and 5 factors. They are 6 items for negative emotion,8 items for despair cognition,6 items for motive deficiency,4 items for perception decrease and 6 items for academic performance.4. Reliability and validity of the test depression scale for university studentsA total of 3508 freshmen from a medical university was tested with the test depression scale for university students for its reliability and validity.4.1 Reliability of the test depression scale for university studentsCronbach'alpha coefficient, Spearman-Brown split half reliability coefficient and the test-retest coefficients of the test scale and 5 factors were between 0.7-0.9. various reliability values of the scale were between 0.8-0.95.4.2 Validity of the test depression scale for university students4.2.1 Structural validityThe exploratory factor analysis of the 30 items in 3508 university students found that the common values of the 30 items were between 0.371-0.768. The 5 common factors can explain 53.906% variance of the 30 items, being up to statistical criteria.4.2.2 Empirical validityThe total scores of the test depression scale for university students was significantly correlated with the total scores of SDS, with the coefficient being up to 0.826; and was significantly correlated with the total scores of HAMD, with a coefficient being up to 0.694. With clinical review results as the golden criteria for diagnosis, the false negative rate of the test depression scale for university students was 4.8%.5. Reliability and validity of final version depression scale for university studentsThe 8262 university students were tested with the final version depression scale for university students for its reliability and validity.5.1 Reliability of the depression scale for university studentsThe internal consistency and split half reliability were tested for the scale and the 5 subscales. The reliability coefficients of the subscale of academic performance were between 0.7-0.8, while the reliability coefficients of the other subscales were between 0.8-0.95. The reliability of the scale was favorably achieved.5.2 Validity of the depression scale for university students5.2.1 Exploratory factor analysisWhen 26 items were kept, the optimal factors structure was achieved, with a KMO value of 0.964 and Bartlett's test result of ?2=99435.060 (p=0.000). The common values of these 26 items were between 0.436-0.751, with factor loads being between 0.487-0.912. By principal components factor analysis to limit extraction of 5 factors and oblique rotation method, the characteristic values of the 5 common factors were respectively 8.129,7.012,6.954,6.923 and 5.018. The 5 common factors can explain 59.618% variance of the 26 items. All the indices were up to the statistical requirements.5.2.2 Confirmatory factor analysis?2/df=2.43. Fit indices of CFI, NFI and GFI were respectively 0.97,0.98 and 0.94. And RMSEA=0.013. The fit between theoretical model and collected data was up to statistical requirements.6. Components of the depression scale for university studentsThe depression scale for university students has 27 items and 5-point scoring of each item, namely 0 for never,1 for seldom,2 for sometimes,3 for often,4 for always. There are 5 subscales, namely 6 items for negative affect,6 items for despair cognition,6 items for motive deficiency,4 items for perception decrease and 4 items for academic performance. In addition, there is 1 appendix item showing the sleeping condition of university students, which is also calculated into the total score. The scorings include total scale score and subscales scores, high score indicating serious depression.7. Norms of the depression scale for university students7.1 Norms of mean±standard deviationFrom the perspective of frequency distribution of the 5 subscales, in the subscale of despair cognition,0 is the most frequently found result, ranging from 49.58% to 80.5%; in the subscale of perception decrease,4 is the most frequently found result, ranging from 1.7%?3.9%. From the perspective of item mean scores, the top 5 high scores are "my thinking and reaction is becoming slow" (1.49±1.01), "I'm less energetic than before"(1.47±1.10), "I can learn nothing recently."(1.45±0.92), "I'm too worried."(1.24±1.07) and "I feel low."(1.23±0.90).7.2 Norms of T scoreThe T score was adopted for standard norm of the depression scale for university students. The primary total score was 25.87±15.68, negative emotion 6.58±4.36, despair cognition 3.17±3.46, motive deficiency 5.69±4.40, perception decrease 5.22±3.42 and academic performance 5.22±3.42. The mean± standard deviation of T scores was 50.00±10.00.7.3 Demarcation points normThe value under ROC curve was 0.923. The standard error of the area was 0.017 and the 95% confidence interval of the area was (0.890,0.956), excluding 0.5. Based on the demarcation point 50.5 of the primary scale score, T score was 66. And at this point, the depression scale for university students had a sensitivity of 0.86, a specificity of 0.85, a correct index of 0.70, a positive likelihood ratio of 5.53 and a negative likelihood ratio of 0.17.As the demarcation point 50.5 of the crude scale score, the use of the depression scale for university students for screening of depression had a positive rate of 7.9% (652 cases of depression) and a negative rate of 92.1%(7610 non-depressed students).8. Factors influencing occurrence of depression in university students8.1 Single factor analysis for depression of university students8.1.1 Demographic factors influencing occurrence of depression in university studentsThe occurrence of depression had no significant gender difference (P>0.05), and other demographic factors including nationality, grade, single child in the family, fresh graduate, science or arts major and resident place of the family did affect the occurrence of depression (P<0.05 or P<0.01). University students of minority, sophomores, non-single child in the family, non-fresh graduates from high schools, arts major students and university students from countryside had higher scale scores, indicating more serious depression symptoms.8.1.2 Personal factors influencing depression of university studentsThe personal factors of being in love, sexual orientation, sexual abuse experience, religion, political belief, belief in second life and mental health counseling experience are all factors significantly influencing depression. The inter-group comparison had statistical significance (P<0.05 or P<0.01). The students not being in love, undefinitive sexual orientation, with sexual abuse, with religion, with no political belief, believing a second life and with mental health counseling experience had higher scale scores, indicating more serious depression.8.1.3 Family factors influencing depression in university studentsThe family factors including the marital status of parents, birth sequence in the family children, core family, educational background of the father and mother, financial income of the family, partly employed or fully employed parents and frequency of parents contact are all significant factors influencing depression of university students. The inter-group comparison had statistical significance (P<0.05 or P<0.01). The depressed students with unfavorable marital status of parents, late birth child, non-core family, the educational background of parents being lower than primary school education, family financial income being less than Y 500, partly-employed parents and less frequent contact with parents had higher scale scores, indicating more serious depression.8.1.4 Illness history factors influencing depression of university studentsPhysical and mental illnesses of university students, mental illness of family members, death of family members from suicide, death of acquaintances from suicide were significant factors influencing depression of university students. The inter-group comparison had statistical significance (P<0.05 or P<0.01). The university students with physical or mental illnesses, mental illness of family members, death of family members from suicide and death of acquaintances from suicide had higher scale scores, indicating more serious depression.8.2 Psychological factors influencing depression of university students8.2.1 Corelationship between depression and psychological factors in university studentsPearson correlation analysis was performed using the scale score and the subscales scores of the depression scale for university students with life significance, self-esteem, family functions, moderation thinking, life events and parenting styles and social support. There was no significant corelationships between depression total scores and despair subscale scores with pursuit of life significance. The other scores all had significant corelationship with depression (P<0.05 or P<0.01). The self-esteem, experience of life significance and life events had the highest correlation with depression, with correlation coefficients of 0.576,0.452 and 0.429.8.2.2 Multiple logistic analysis of factors influencing depression in university studentsWith the scale total score of depression as the dependent variable and with experience of life significance, pursuit of life significance, self-esteem, family function scores, moderation thinking scores, life event total scores,6 subscales scores of parents parenting styles,3 subscales scores of social support as the independent variables, the multiple logistic analysis was performed to find the factors predicting depression in university students. The correlation coefficient of multiple logistic analysis between the 15 independent variables and depression was 0.690 and the square multiple correlation coefficient was 0.476, indicating the 15 independent variables can explain 47.6% variance of depression in university students. In the logistic model, the significant predictors of depression in university students were 11 independent variables including experience of life significance. From the perspective of standardized logistic coefficient, the beta coefficient abstract value of self-esteem, life events and experience of life significance were comparatively greater, indicating these 3 predictors having a higher explanation power for depression in university students. The logistic coefficients of moderation thinking, mother refusal, mother's love and overprotection by father did not reach statistical significance, indicating these 4 predictors having small explanation power for variance of depression in university students.8.2.3 Path analysis of interaction between depression and psychological factorsAmong the paths influencing depression in university students, there were 7 significant paths. The most significant path was life event?utility of social support?experience of life significance?self-esteem?total score of depression, indicating social support, life significance and self-esteem plays a mediating or buffering role in the process of from stressful life event to occurrence of depression.8.3 Logistic regression analysis of risk factors contributing to depression in university studentsWith depression or no depression as the dependent variables,0 indicates no depression and 1 indicate depression. With 34 significant factors influencing depression found in single factor analysis and multiple factors analysis as the independent variables, Logistic regression analysis was performed. The Wald indicators of grade, educational background of the mother, pursuit of life significance, father refusal, overprotection by the mother, self-esteem, subjective support, utility of the social support and life events were between 4.568 and 267.443, being significant at the level of 0.05:The OR values were between 1.141 and 1.311, all above 1, indicating these 13 variables have significant relevance with depression and no depression groups and these 13 variables are the important risk factors of depression in university students.Conclusions of the study1. The items pool for the depression scale is characteristically for university students, with wide coverage and can show the symptoms of depression in university students.2. The various reliability and validity indicators of the test depression scale and the final depression scale are up to the statistical requirements.3. The norms of the depression scale for university students are indicated to Chinese university students, especially the norms of freshmen, sophomore and junior, which can provide a standard for further studies.4. There are many factors contributing to depression in university students, which can be categorized into personal factors, family factors, social factors. And self-esteem, stressful life event and experience of life significance are the most important factors.Features and creativities of the study1. The achievement of the study, the depression scale for university students, is the first diagnostic tool specifically for university students, which provides an effective tool for the early diagnosis of depression in university students.2. We established the norms of mean±standard deviation, T score, demarcation point, which are the first norms specifically formulated for university students. These. norms provide a standard for diagnosis of depression and depression severity.The limitations of the study and the predication of further studies1. A mature scale needs again and again verification. Therefore, the reliability and validity of the scale as well as the usefulness of the scale need verification by further studies and its applications.2. The samples of senior students are insufficient in this study. And the further study need more samples of seniors to improve the norms of each grade.3. The norms may change with the social development. Therefore, the norms of this study may need renewal several years later.4. The scale is formulated based on data from Chinese university students. Further studies may extend its use to university students from eastern countries to verify its effectiveness. |
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