Effective use of the tool and the relationship between self-rated health and depression risk
To provide a basis for the effective use of the self-rated health assessment tool, we compared the three groups of children based on their physical/mental conditions together with the duration of those conditions (Favorable Health: rating their physical/mental health condition as “Good/Relatively good/Normal”; Temporarily Poor Health: “Relatively bad/Bad” + “not persisting for two weeks”; and Persistently Poor Health: “Relatively bad/Bad” + “persisting for two weeks or longer”).
In the domain of self-rated physical health, 85.3% of all children belonged to the Favorable Health group, whereas those belonging to the Temporarily and Persistently Poor Health groups accounted for 8.1% and 6.6%, respectively. There were significant differences related to school type, but no sex based differences were observed. In the domain of self-rated mental health, 85.7% of all children belonged to the Favorable Health group, whereas those belonging to the Temporarily and Persistently Poor Health groups accounted for 5.4% and 8.9%, respectively. There were significant differences related to both sex and school type (Table 5).
Next, we compared the prevalence of depression among the three groups. In the domain of self-rated physical health, the mean DSRS-C score for each group was as follows: Favorable Health: 11.11 ± 5.92, Temporarily Poor Health: 14.71 ± 6.12, and Persistently Poor Health: 17.36 ± 6.68. The Persistently Poor Health group had significantly higher DSRS-C scores than the Temporarily Poor and Favorable Health groups, while the scores for the Temporarily Poor Health group were significantly higher than those for the Favorable Health group. Similarly, in the domain of self-rated mental health, the mean DSRS-C score for each group was as follows: Favorable Health: 10.77 ± 5.61, Temporarily Poor Health: 16.50 ± 5.81, and Persistently Poor Health: 19.09 ± 6.12. The Persistently Poor Health group had significantly higher scores than the Temporarily Poor and Favorable Health groups, while the scores for the Temporarily Poor Health group were significantly higher than those for the Favorable Health group. As for the DSRS-C cutoff (16), the Persistently Poor Health group had higher self-rated physical health scores, and the Temporarily Poor Health and Persistently Poor Health groups had higher self-rated mental health scores (Tables 6 and 7).
Table 5
Sex- and school type-based analysis of self-rated physical and mental health of school students
| Self-rated physical health | | Self-rated mental health | |
Favorable Health | Temporarily Poor Health | Persistently Poor Health | | Favorable Health | Temporarily Poor Health | Persistently Poor Health | |
P | P |
School | n | % | n | % | n | % | | n | % | n | % | n | % | |
Elementary | 1417 | 89.0% | 110 | 6.9% | 65 | 4.1% | < 0.001 | 1435 | 90.1% | 74 | 4.6% | 83 | 5.2% | < 0.001 |
Junior High | 1588 | 84.7% | 136 | 7.3% | 151 | 8.1% | 1601 | 85.4% | 98 | 5.2% | 176 | 9.4% |
Senior High | 1806 | 83.1% | 210 | 9.7% | 158 | 7.3% | 1799 | 82.8% | 132 | 6.1% | 243 | 11.2% |
Boys | 2408 | 85.3% | 233 | 8.3% | 183 | 6.5% | 0.824 | 2466 | 87.3% | 142 | 5.0% | 216 | 7.6% | 0.001 |
Girls | 2403 | 85.3% | 223 | 7.9% | 191 | 6.8% | 2369 | 84.1% | 162 | 5.8% | 286 | 10.2% |
Total | 4811 | 85.3% | 456 | 8.1% | 374 | 6.6% | < 0.001 | 4835 | 85.7% | 304 | 5.4% | 502 | 8.9% | < 0.001 |
Chi-squared test for comparison of percentages |
Table 6
Self-rated physical health of DSRS-C scores between the three groups
Self-rated physical health |
DSRS-C | Favorable Health n = 4811 | | Temporarily Poor Health n = 456 | | Persistently Poor Health n = 374 | P |
Mean | | SD | | Mean | | SD | | Mean | | SD | |
11.11 | ± | 5.92 | | 14.71 | ± | 6.12 | | 17.36 | ± | 6.68 | |
| Favorable Health༜Temporarily Poor Health༜Persistently Poor Health | < 0.001 |
Variance analysis (one factor and three levels) was performed, and Tukey's method was used for multiple comparisons. |
All data are presented as mean ± SD; one-way ANOVA with post hoc Tukey test was applied for significance testing.
p value is significant at < 0.05
Table 7
Self-rated mental health of DSRS-C scores between the three groups
| Favorable Health n = 4835 | | Temporarily Poor Health n = 304 | | Persistently Poor Health n = 502 | |
| | P |
DSRS-C | Mean | | SD | | Mean | | SD | | Mean | | SD | |
10.77 | ± | 5.61 | | 16.50 | ± | 5.81 | | 19.09 | ± | 6.12 | |
| Favorable Health༜Temporarily Poor Health༜Persistently Poor Health | < 0.001 |
Variance analysis (one factor and three levels) was performed, and Tukey's method was used for multiple comparisons. All data are presented as mean ± SD; one-way ANOVA with post hoc Tukey test was applied for significance testing.
p value is significant at < 0.05
When asked about their physical health conditions, many children in the Persistently Poor Health group answered that the body part responsible was their “head” (17.7%), “abdomen, stomach, intestines” (11.8%), or “low back, shoulder, neck, whole body (25.1%).” Common reasons included: “I have abdominal pain,” “I have a headache,” “I can’t sleep,” “I have a stiff neck and shoulders,” “I often vomit,” and “I get tired easily.” The leading cause of poor mental health in this group was “school” (58.9%), followed by “home” (15.8%), and “other” (including N/A) (25.3%). The most common reasons included: “I feel tired,” “I feel gloomy,” “There are many things to worry about,” “I care about what other people think,” “Stress,” “Anxiety,” “No fun at all,” “Bullying,” and “I don’t understand what I study.” “School” (59.8%) was the leading cause in the Temporarily Poor Health group as well, followed by “home” (10.8%), and “other” (including N/A) (29.5%). There were no significant differences between these groups (Table 8).
Table 8
Leading causes of poor mental health in Temporarily Poor Health and Persistently Poor Health groups
| Temporarily Poor Health | Persistently Poor Health | | | Total |
P | |
| n | % | n | % | | n | % |
School | 179 | 59.8% | 300 | 58.9% | 0.083 | 479 | 59.4% |
Home | 48 | 10.8% | 54 | 15.8% | 102 | 12.7% |
Other | 77 | 29.5% | 148 | 25.3% | 225 | 27.9% |
Chi-squared test for comparison of percentages |
Moreover, to assess the self-rated health screening tool, we calculated sensitivity, specificity, false positive fraction, false negative fraction, prevalence rate, positive predictive value, and negative predictive value by matching with DSRS-C cutoff values (Tables 9 and 10).
Table 9
Results of self-rated physical health measurements by matching with DSRS-C cutoff values
Self-rated physical health | Over-16 Diseased | Under-16 Disease-free | Total (n) |
Screened positive | 226 | 148 | 374 |
Screened negative | 1329 | 3938 | 5267 |
Total (n) | 1555 | 4086 | 5641 |
Sensitivity | 14.5% | | |
Specificity | 96.4% | | |
False positive fraction | 3.6% | | |
False negative fraction | 85.5% | | |
Prevalence rate | 27.6% | | |
Positive predictive value | 60.4% | | |
Negative predictive value | 74.8% | | |
Table 10
Results of self-rated mental health measurements by matching with DSRS-C cutoff values
Self-rated mental health | Over-16 Diseased | Under-16 Disease-free | Total (n) |
Screened positive | 531 | 275 | 806 |
Screened negative | 1024 | 3811 | 4835 |
Total (n) | 1555 | 4086 | 5641 |
Sensitivity | 34.1% | | |
Specificity | 93.3% | | |
False positive fraction | 6.7% | | |
False negative fraction | 65.9% | | |
Prevalence rate | 27.6% | | |
Positive predictive value | 65.9% | | |
Negative predictive value | 78.8% | | |
Regarding the results of self-rated physical health measurements obtained by matching with DSRS-C cutoff values, sensitivity was 14.5%, while false negative fraction was 85.5%; however, specificity was 96.4% and false positive fraction was 3.6%. Therefore, positive results indicated definite depressive states.
Regarding the results of self-rated mental health measurements obtained by matching with DSRS-C cutoff values, sensitivity was 34.1%, false negative fraction was 65.9%, specificity was 93.3%, and false positive fraction was 6.7%. Therefore, positive results indicated definite depressive states.