Abstract
Background
Grit, defined as the perseverance and passion for long-term goals, plays an essential role in academic success and resilience in the medical profession. Previous cross-sectional studies have indicated an association between higher grit and fewer depressive symptoms among medical residents. However, no longitudinal studies have examined the association between grit and later depressive symptoms during residency training. Therefore, this study explored the association between grit at the start and depressive symptoms at the end of the first-year postgraduate (PGY1) residency among Japanese medical residents.
Methods
This longitudinal study analyzed data from all first-year postgraduate residents at the Tokyo Medical and Dental University in Tokyo, Japan, from 2021 to 2023. We administered the surveys at the start and end of PGY1. We assessed grit using the Japanese version of the Short Grit Scale (Grit-S) and depressive symptoms using the Center for Epidemiologic Studies Depression Scale. We examined the association between grit at the baseline and depressive symptoms at the end of PGY1 using logistic regression analysis.
Results
Of the 146 residents, 28 (19.2%) exhibited depressive symptoms by the end of PGY1. After adjusting for baseline depressive state, age, sex, university attended, sleeping hours, and training program, a 1-unit increase in the Grit-S score was associated with a significantly reduced likelihood of depressive symptoms (adjusted odds ratio [AOR]: 0.43; 95% confidence interval [CI]: 0.18–0.98). The crude analysis indicated that the perseverance of effort score was associated with a smaller reduction in the risk of having depressive symptoms at the end of PGY1 (AOR: 0.51; 95% CI: 0.29–0.93); however, the consistency of interest score was not (AOR: 0.56; 95% CI: 0.30–1.05).
Conclusion
This study demonstrated that, among Japanese medical residents, higher grit at the start of residency is significantly associated with a lower risk of depressive symptoms by the end of PGY1.
Clinical trial number
Not applicable.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12909-025-07651-4.
Keywords: Grit, Depressive symptoms, Depression, Medical resident, Longitudinal study
Introduction
The medical profession is inherently stressful, with a high prevalence of depressive symptoms, burnout, and other mental health issues [1, 2]. In particular, resident physicians may be at an elevated risk of developing depressive symptoms due to their recent transition from medical student to resident physician, and their lack of communication skills, medical knowledge, and experience [3]. In a large cross-sectional survey in Japan, 22.6% of first-year postgraduate (PGY1) residents demonstrated new depressive symptoms after 3 months of resident training [4]. Residents with depressive symptoms tended to make more medical errors than did those without them [3, 5, 6]. Thus, it is crucial to identify residents at risk for depression to provide timely preventive support.
Grit, as coined and defined by Angela Duckworth, is the passion and perseverance for long-term goals [7]. Grit has garnered significant attention in medical literature for its positive association with academic achievement, career success, and psychological well-being, as well as its negative association with depression, burnout, and residency attrition [8]. Our previous cross-sectional study showed that, in Japan, PGY1 residents with high grit scores had fewer depressive symptoms, compared with those with lower scores at the beginning of their residency [9]. Another cross-sectional study also demonstrated that the total score on the grit scale and the scores for its two subscales—perseverance of effort and consistency of interest scores—were inversely associated with depressive symptoms in medical students [10]. A cross-sectional study from the USA showed that, among surgical residents, high grit was inversely associated with depressive symptoms and positively predictive of psychological well-being [11].
Although several studies have demonstrated an association between grit and depressive symptoms among resident physicians [9, 11], longitudinal studies are lacking. Cross-sectional studies provide valuable insights; however, in a cross-sectional design, there is the potential for reverse causality, with individuals with greater depressive symptoms showing lower grit scores. Longitudinal studies will allow researchers to examine whether grit at the start of residency is associated with fewer depressive symptoms in the later period, after adjusting for depressive symptoms that are present at the start of residency. This information can inform the development of targeted interventions to support the well-being of residents. This study aimed to fill this gap in the literature by conducting a longitudinal study that examine the association between grit at the start of residency and depressive symptoms at the end of PGY1 residency among Japanese medical residents.
Methods
Study participants
This longitudinal cohort study was conducted at the Tokyo Medical and Dental University (TMDU) in Tokyo, Japan. For this study, we initially recruited all PGY1 residents (N = 284) who joined the TMDU Resident Program in 2021, 2022, and 2023. We conducted a baseline online survey approximately at the start of the PGY1 residency, in April. We conducted a follow-up survey at the end of the PGY1 residency, in March. The online survey, administered in Japanese, included items assessing grit using the Japanese version of the Short Grit Scale (Grit-S) [12], depressive symptoms using the Japanese version of the Center for Epidemiologic Studies Depression Scale (CES-D) [13], and other covariates adapted from a previous cross-sectional study [9]. Japanese residency programs provide a comprehensive 2-year training experience that requires residents to rotate through major specialties at approved hospitals throughout Japan. The TMDU residency program can be divided into two main types. Program 1 involves PGY1 training in the TMDU Hospital, an academic medical center and tertiary emergency medical facility, and PGY2 training in a community-based hospital. Program 2 involves PGY1 training in a community-based hospital and PGY2 training in the TMDU Hospital. This program has been a standard practice since 2004 [14]. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Institutional Review Board of Tokyo Medical and Dental University (IRB approval number M2019-283). Informed consent was obtained from all participants prior to their participation in the study. Residents who did not provide consent or failed to complete all the surveys were excluded. Therefore, there were no missing data for the residents who participated in this study.
Grit
We assessed grit among PGY1 residents at the start of the PGY1 residency using the Japanese version of Grit-S, which was verified for factor structure, reliability, and validity among 1043 Japanese university students [12]. Grit-S was designed as a modified version of the original Grit Scale [15] and consisted of eight items, rated using a 5-point Likert scale [16]. The final scores for each question were summed and then divided by the number of questions to yield scores ranging from 1 (not at all gritty) to 5 (extremely gritty). The two subscales, namely the perseverance of effort and consistency of interest, consisted of four items with similar score ranges as the total grit score. Grit-S was validated for internal consistency, test-retest stability, and predictive validity [16]. The Cronbach’s alpha in our study were 0.75, 075, and 0.65 for Grit-S and the perseverance of effort and consistency of interest subscales, respectively. The continuous Grit-S, perseverance of effort, and consistency of interest scores were analyzed. The Grit-S scores were measured during the baseline survey. We obtained the Japanese version from the validation study [12], and because our use was solely for research purposes with proper citation, no additional licensing or permission procedures were deemed necessary.
Depressive symptoms
Depressive symptoms were measured using the Japanese version of the CES-D [13], which was validated using the original CES-D, a widely recognized scale for assessing depressive symptoms over the past week [17]. According to the international standard cutoff value, we defined a score ≥ 16 points on the CES-D as indicative of depressive symptoms and utilized the scores as a categorical variable in the analysis [18]. In a validation study of the Japanese version of the CES-D, a cutoff score of 16 points demonstrated a sensitivity of 88.2% and a specificity of 84.8% [13]. However, a cut-off value of 19 points was recently established for Japanese workers, demonstrating an area under the receiver operating characteristic curve of 0.96 [19]. Therefore, we performed a sensitivity analysis using a cutoff value of 19 points. We collected the CES-D scores by administering online surveys at two time points (at the start and end of the PGY1 residency). We conducted email-based interventions and follow-up interviews with residents identified as having depressive symptoms at the two time points.
Covariates
We collected data on several covariates from the basic data at the start of the PGY1 residency, including demographic variables such as age, sex, start year of training, type of training program, and university attended. We obtained information on the type of residency program to determine if the PGY1 training environment was a different TMDU hospital from a community-based hospital. The name of the university attended was identified to assess familiarity with the training environment, as residents who graduated from TMDU were more familiar with it because of their clinical clerkship at the TMDU hospital. Additionally, data on lifestyle factors were collected during the baseline online survey at the start of the PGY1 residency, including average sleeping hours on weekdays, smoking habits (categorized as never, past smoker, or current smoker), alcohol consumption habits (categorized as never, only a few times a month, or more than a few times a week), frequency of eating breakfast (categorized as every day, more than several times a week, or less than a few times a week), and frequency of exercise within the previous month (categorized as almost never, less than a few times a week, or more than several times a week).
Statistical analysis
We calculated descriptive statistics for all variables to compare the differences between residents with and without depressive symptoms at the end of PGY1 residency. We also compared the characteristics of residents who completed the follow-up surveys (participants) and those who did not respond at the follow-up. Continuous data were compared using Wilcoxon rank-sum test. Categorical data were presented as counts with percentages (%) and were compared using Fisher’s exact test if at least one expected cell count was < 5 or else using the chi‑squared test. We used logistic regression analysis to evaluate the association between the baseline total Grit-S scores and presence of depressive symptoms at the end of PGY1 as the primary outcome. We evaluated the association between the Grit-S subscales (perseverance of effort and consistency of interest) scores and presence of depressive symptoms at the end of PGY1 as secondary outcomes. We adjusted for potential confounders, including baseline depressive state, age, sex, university attended, average weekday sleeping hours, and type of residency program, according to previous studies [9, 20]. We presented the results as odds ratios (OR) with 95% confidence interval (CI). To examine the changes in depressive symptoms over time by grit level, we categorized the participants into three groups based on their Grit-S scores: low grit (< 1 standard deviation [SD] from the cohort mean), mid-range grit (within ± 1 SD of the mean), and high grit (> 1 SD from the mean). We calculated the mean CES-D scores and corresponding 95% CIs for each of three grit groups at both time points. The mean trajectories and 95% CIs were visualized using line graphs with shaded areas representing the CIs. Additionally, we conducted Wilcoxon signed-rank tests within each grit group to evaluate the statistical significance of the changes in the CES-D scores between baseline and the follow-up. We also compared the changes in CES-D scores between the grit groups using Wilcoxon rank-sum test. For the sensitivity analysis, we conducted an additional logistic regression limited to participants who did not have depressive symptoms at baseline (a CES-D score < 16 points) to specifically evaluate the association between grit and new-onset depressive symptoms at the end of PGY1. Statistical significance was set at a two-tailed p-value < 0.05. All analyses were conducted using Stata version 17.0 (Stata Corp LLC, College Station, TX, USA).
Results
As shown in Figs. 1 and 284 PGY1 residents joined the TMDU Resident Program between April 2021 and March 2024. Residents who disagreed to participate (N = 2) or had no response (N = 51) or had missing values in the baseline survey (N = 9) were excluded from the study. A total of 221 residents participated in the study and completed the baseline survey, of whom 76 (34.2%) residents did not respond at the follow-up. Thus, 146 residents were included in the analysis.
Fig. 1.
Flow chart of the participants included in the study
As shown in Table 1, among 146 residents, 28 (19.2%) residents had depressive symptoms at the end of their PGY1 residency. The Grit-S score at baseline was significantly lower in the residents with depressive symptoms than in those without depressive symptoms (mean: 2.96 ± 0.55 vs. 3.31 ± 0.59). Regarding the Grit-S subscales scores, the perseverance of effort score of the residents with depressive symptoms was significantly lower than that of those without depressive symptoms (3.25 ± 0.68 vs. 3.58 ± 0.69). The consistency of interest score was significantly lower in the residents with depressive symptoms than in those without depressive symptoms (mean: 2.66 ± 0.62 vs. 3.03 ± 0.75). Additionally, a higher percentage of the residents in the residents with depressive symptoms had depressive symptoms at baseline compared with those without depressive symptoms (50.0% vs. 14.4%). Supplementary Table 1 shows the results of dropout analysis between the residents who completed the follow-up surveys and those who did not respond at the follow-up. Compared with the residents who completed the follow-up surveys, residents who did not respond at the follow-up were more likely to be enrolled in program 1 (71.1% vs. 32.2%) and to have started residency in 2021 (51.3% vs. 33.6%) and were less likely to eat breakfast every day (48.7% vs. 67.8%).
Table 1.
Characteristics of study participants
| Depressed N = 28 (19.2) |
Non-Depressed N = 118 (80.8) |
p-value | |
|---|---|---|---|
| Age (years), mean (SD) | 25.2 (1.33) | 24.9 (1.92) | 0.440 |
| Sex, n (%) | |||
| Male | 18 (64.3) | 67 (56.8) | 0.469 |
| Female | 10 (35.7) | 51 (43.2) | |
| Start year of training, n (%) | 0.809 | ||
| 2021 | 9 (32.1) | 40 (33.9) | |
| 2022 | 7 (25.0) | 23 (19.5) | |
| 2023 | 12 (42.9) | 55 (46.6) | |
| Graduated university, n (%) | 0.936 | ||
| TMDU | 14 (50.0) | 58 (49.2) | |
| Others | 14 (50.0) | 60 (50.8) | |
| Type of residency program | 0.371 | ||
| Program 1 | 11 (39.3) | 36 (30.5) | |
| Program 2 | 17 (60.7) | 82 (69.5) | |
| Marriage, n (%) | 0 (0) | 5 (4.2) | 0.583 |
| Presence of family living together, n (%) | 1 (3.6) | 20 (17.0) | 0.078 |
| Weekday sleeping hours, mean (SD) | 7.26 (1.22) | 7.32 (0.90) | 0.764 |
| Smoking habits, n (%) | 0.051 | ||
| Never | 27 (96.4) | 109 (92.4) | |
| Past smoker | 0 (0) | 9 (7.6) | |
| Current smoker | 1 (3.6) | 0 (0) | |
| Drinking habits, n (%) | 0.066 | ||
| Never | 6 (21.4) | 16 (13.6) | |
| Only a few times a month | 18 (64.3) | 60 (50.9) | |
| More than a few times a week | 4 (14.3) | 42 (35.6) | |
| Frequency of eating breakfast, n (%) | 0.454 | ||
| Every day | 21 (75.0) | 78 (66.1) | |
| More than several times a week | 2 (7.1) | 21 (17.8) | |
| Less than a few times a week | 5 (17.9) | 19 (16.1) | |
| Frequency of exercise within the last month, n (%) | 0.143 | ||
| More than several times a week | 3 (10.7) | 33 (28.0) | |
| Less than a few times a week | 11 (39.3) | 33 (28.0) | |
| Almost never | 14 (50.0) | 52 (44.0) | |
| Grit-S, mean (SD) | 2.96 (0.55) | 3.31 (0.59) | 0.005 |
| Perseverance of Effort, mean (SD) | 3.25 (0.68) | 3.58 (0.69) | 0.023 |
| Consistency of Interest, mean (SD) | 2.66 (0.62) | 3.03 (0.75) | 0.016 |
| Depressed at baseline, n (%) | 14 (50.0) | 17 (14.4) | < 0.001 |
Bold indicates p < 0.05.
As shown in Table 2, the crude analysis revealed each one-unit increase in the Grit-S score at baseline was associated with a significantly reduced likelihood of depressive symptoms (OR: 0.36; 95% CI: 0.17–0.75). After further adjusting for depressive symptoms at baseline, age, sex, university attended, weekday sleeping hours, and type of residency program, this association remained statistically significant (adjusted odds ratio [AOR]: 0.43; 95% CI: 0.18–0.98).
Table 2.
Logistic regression analysis of the association between depressed state at the end of PGY1 and Grit-S score
| Crude | Adjusted | |||
|---|---|---|---|---|
| Odds ratio | 95%CI | Odds ratio | 95%CI | |
| Grit-S | 0.36 | 0.17–0.75 | 0.43 | 0.18–0.98 |
Adjusted for depressed state at baseline, age, sex, graduated university, weekday sleeping hours, and type of residency program. Bold indicates p < 0.05
As shown in Table 3, the crude analysis indicated that a 1-unit increase in the perseverance of effort score was associated with a smaller reduction in the risk of having depressive symptoms at the end of PGY1 (AOR: 0.51; 95% CI: 0.29–0.93). However, the consistency of interest score was not significantly associated with depressive symptoms (AOR: 0.56; 95% CI: 0.30–1.05). After further adjusting for depressive symptoms at baseline, age, sex, university attended, weekday sleeping hours, and type of residency program, the perseverance of effort score (AOR: 0.54; 95% CI: 0.27–1.06) and consistency of interest score (risk ratio: 0.61; 95% CI: 0.32–1.16) were not significantly associated with a lower risk of having depressive symptoms.
Table 3.
Logistic regression analysis of the association between depressed state at the end of PGY1 and Grit-S subscale scores
| Crude | Adjusted | |||
|---|---|---|---|---|
| Odds ratio | 95%CI | Odds ratio | 95%CI | |
| Perseverance of effort | 0.51 | 0.29–0.93 | 0.54 | 0.27–1.06 |
| Consistency of interest | 0.56 | 0.30–1.05 | 0.61 | 0.32–1.16 |
Adjusted for depressed state at baseline, age, sex, graduated university, weekday sleeping hours, and type of residency program. Bold indicates p < 0.05
Figure 2 illustrates the change in the mean CES-D scores from baseline to follow-up, stratified by grit group. Participants in the low grit group had the highest CES-D scores at both time points (baseline = 14.3 [95% CI, 12.0–16.6]; follow-up = 13.9 [9.0–18.8]), with a non-significant in depressive symptoms over time (mean difference = − 0.46, p = 0.83). The high grit group showed the lowest CES-D scores and a non-significant reduction in depressive symptoms (baseline = 11.3 [10.1–12.5]; follow-up = 10.2 [8.5–11.8]; mean difference = − 1.12, p = 0.28). The mid-range grit group demonstrated intermediate CES-D scores and a non-significant decline in depressive symptoms (baseline = 12.4 [11.1–13.7]; follow-up = 11.5 [10.1–12.9]; mean difference = − 0.95, p = 0.29). There were no significant differences in depressive symptom changes between the low and mid-range grit groups (mean difference = 0.49, 95% CI: − 3.49–4.46, p = 0.81) or between the low grit and high grit groups (mean difference = 0.66, 95% CI: − 4.07– 5.39, p = 0.78).
Fig. 2.
CES-D score change from baseline to the follow-up by Grit Category
In a sensitivity analysis, we used a score of ≥ 19 points on the CES-D as indicative of depressive symptoms. Among 146 residents, 16 (11.0%) and 20 (13.7%) had depressive symptoms at the start and end of their PGY1 residency, respectively. The crude analysis revealed that the Grit-S score at baseline was associated with a significantly reduced likelihood of depressive symptoms (OR:0.33; 95% CI: 0.14–0.76). However, this alternative definition yielded no statistically significant association with the Grit-S score after adjustment (AOR: 0.39; 95% CI: 0.15–1.00). Moreover, in a crude analysis restricted to the residents without depressive symptoms at baseline (CES-D score < 16 points), the baseline Grit-S score was not associated with lower odds of having the subsequent depressive symptoms (OR: 0.63; 95% CI: 0.24–1.62).
Discussion
In this longitudinal study, we found that higher baseline grit scores among PGY1 residents were significantly associated with a reduced risk of developing depressive symptoms by the end of their PGY1 residency. This association remained significant even after adjusting for baseline depressive symptoms and other covariates such as age, sex, university attended, average weekday sleeping hours, and type of residency program. Our findings are consistent with those of previous cross-sectional studies suggesting a protective effect of grit against depressive symptoms in Japan and the USA [9, 11]. However, no longitudinal studies have examined whether grit is associated with later depressive symptoms during residency training after adjusting for baseline depressive symptoms. Because there is potential for reverse causality in a cross-sectional design, our longitudinal study adds to the literature by demonstrating that higher grit serves as a predictor of depressive symptoms one year later in a clinical training setting.
The following pathways may explain how high grit protects against depressive symptoms. First, occupational stress mediates the relationship between grit and depression [21]. Individuals with high grit can recover faster from negative emotions [22], have lower psychological exhaustion [23], and use negative events as an opportunity for growth [21]. In addition, they may know how to cope with stressful environments and have increased psychological security [24]. This can reduce interpersonal stress, thereby reducing the risk for depression [24]. Second, presence of meaning in life may mediate the association between grit and depression [25]. Individuals with high grit are more likely to realize that life is meaningful and to stay motivated to look for meaning in their lives; therefore, they are less likely to experience maladaptive emotional states. Third, mindfulness may mediate the association between grit and well-being [26, 27]. Individuals with high grit have higher levels of mindfulness, which may protect against depressive symptoms. Future research should examine whether occupational stress, presence of meaning in life, and mindfulness mediate the association between grit and depressive symptoms among medical residents, which could not be evaluated in this study.
Finally, through univariate analysis, we found that perseverance of effort was significantly associated with later depressive symptoms, whereas consistency of interests was not. Perseverance of effort represents sustained effort toward long-term goals despite setbacks and distress. Consistency of interest represents passion, dedicated time, attention, and commitment toward long-term goals. A previous study with a large international sample found that perseverance of effort, but not consistency of interest, was related to lower levels of depression [28]. Another study also explored the mechanisms and suggested that authentic pride and perceived power mediated the relationship between perseverance of effort and depression [29]. Although multivariate analysis in our study showed that perseverance of effort was not significantly associated with later depressive symptoms, these results of previous studies underscore the importance of fostering perseverance of effort to reduce the risk of developing depressive symptoms.
Our study has important strengths. This is the first longitudinal study to evaluate the impact of grit on depressive symptoms after a 1-year residency program by adjusting for baseline depressive states and other covariates. However, there are several limitations to consider. First, this study was conducted at a single institution, which may limit the generalizability of our results to other residency programs. Second, the self-reported measures of grit and depressive symptoms may have introduced response biases, such as social desirability bias, affecting the validity of the data collected. Third, there were significant differences regarding the year of training initiation and type of residency program between the residents who did not respond at the follow-up and participants. Specifically, in the early study years (2021 and 2022), follow-up communication may have been insufficient, and residents in program 1 may have had lower response rates because they may have been preparing to work at external hospitals during the follow-up surveys. These issues may have introduced selection bias, warranting a cautious interpretation of our results. Fourth, although the confounding factors in our analysis were selected based on previous studies [9, 20], important variables such as smoking habits, which showed borderline significance in the univariate analysis, should have ideally been included in the sensitivity analyses. However, owing to the small number of smokers, we were unable to include smoking as an adjustment variable in the multivariate analysis, potentially resulting in residual confounding. Additionally, we were unable to assess or adjust for other important confounders, such as prior mental health status, coping styles, or significant life events, which may have influenced both grit and depressive symptoms. The absence of these variables may have contributed to unmeasured confounding in our models. Fifth, we utilized a self-administered questionnaire and identified residents with a CES-D score ≥ 16 points who were categorized as having depressive symptoms. However, this threshold does not equate to a formal diagnosis of depression, and should hence be interpreted with caution. In accordance with previous studies in Japan [19], we also conducted a sensitivity analysis using an alternative cutoff of a CES-D score ≥ 19 points. However, this analysis did not yield significant results. The inconsistency in the results depending on the selected cutoff for the CES-D score indicates the need for caution when interpreting these associations. Sixth, the CES-D scores were generally higher at the beginning of residency and appeared to decline after 1 year. Additionally, we stratified the participants based on their baseline Grit-S scores to explore differences in the evolution of depressive symptoms over time among residents with high, mid-range, and low grit levels. Moreover, we conducted a sensitivity analysis restricted to the residents who did not have depressive symptoms at baseline, and evaluated the onset of new depressive symptoms during follow-up. This analysis did not reveal significant results, suggesting that baseline grit does not play a protective role in the development of new-onset depressive symptoms during residency. Seventh, although our sample size included 28 individuals for the outcome and 6 adjustment variables, the analyses of the Grit-S subscales and subgroup sensitivity analyses may have lacked sufficient statistical power to detect significant effects. Future studies with larger sample sizes are needed to enhance the statistical power and robustness of these findings. Finally, we acknowledge the possibility of a reciprocal relationship between grit and depressive symptoms. Because grit was assessed only at baseline and not at follow-up, we were unable to conduct cross-lagged analyses to test this bidirectional effect. Nevertheless, our longitudinal design and statistical adjustments, including baseline depressive states, partially address this concern.
Implications
In this study, we demonstrated that low grit scores at the start of PGY1 residency were significantly associated with depressive symptoms at the end of the residency. Residency program directors should evaluate the grit scores of resident physicians at the start of employment and closely follow residents with low grit scores. Providing interventions, such as resilience training [29, 30], mentorship programs [31], and periodic psychological assessments, to residents with low grit may be beneficial in supporting their mental health. Additionally, addressing organizational resilience factors, such as mitigating long working hours, facilitating easier access to supervisors and occupational physicians, and improving overall workplace support, should also be considered as critical strategies. These proactive approaches may enhance individual well-being and improve the overall residency program outcomes by reducing attrition rates and improving clinical performance.
Conclusion
In conclusion, low grit scores at the start of PGY1 residency were significantly associated with depressive symptoms at the end of residency among Japanese residents. These findings suggest that grit is an important protective factor against depressive symptoms among resident physicians. Further research is required to examine whether interventions aimed at increasing grit during residency training can prevent depressive symptoms and other mental health problems among resident physicians.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Acknowledgements
We are grateful to staffs at Department of Professional Development, Institute of Science Tokyo Hospital for assisting with survey collection.
Abbreviations
- PGY1
first-year postgraduate
- TMDU
Tokyo Medical and Dental University
- Grit-S
Short Grit Scale
- CES-D
Center for Epidemiologic Studies Depression Scale
- RR
Relative risk
- CI
Confidence interval
Author contributions
NN, YA, EO, AK, and MY acquired and designed the study. TN analyzed the study and drafted the work. NN substantively revised the study. TF and MY approve the submitted version and agree to be personally accountable. All authors read and approved the manuscript.
Funding
This work was supported by Ministry of Health, Labour and Welfare Research Grant Number 24AC1002. The grant was awarded to MY.
Data availability
Data from this study will be available on reasonable request from the corresponding author.
Declarations
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Ethical approval and consent to participate
This study was approved by the Institutional Review Board of Tokyo Medical and Dental University (IRB approval number M2019-283). We obtained informed consent from all participants before participation in the study. We conducted this study in accordance with the Declaration of Helsinki.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data from this study will be available on reasonable request from the corresponding author.