Introduction

Depression and anxiety are considered the most frequent mental disorders in the world; they cause disability, mortality, and loss of productivity (^{Klumpp & Shankman, 2018}).

Mental and behavioral disorders account for 14% of the global of disease burden and are one of the leading causes of disability worldwide, collectively accumulating more than 40 million years lost due to disability among people aged 20 to 29 during 2010 (^{Institute for Health Metrics and Evaluation, Human Development Network, & World Bank, 2013}).

People whose work involves caring or assisting other people suffer from emotional exhaustion, depersonalization, and under personal achievement that make them more susceptible to depressive disorders (^{Maslach, Jackson, & Leiter, 1996}).

In medical students it has been reported that tobacco use is higher when they have depression or anxiety compared to those who do not have it (31% vs. 19%, p < .007) (^{Romero, Santander, Hitschfeld, Labbé, & Zamora, 2009}).

In another study, medical residents responded that they felt excessively tired and that the workload did not allow them to care for other areas of their lives (^{Saravanan & Wilks, 2014}).

In Mexico, ^{Martínez-Lanz, Medina-Mora, and Rivera (2005)} reported that 47.5% of medical residents have depressive symptoms, 16.4% have high stress levels, 55% use tobacco, 65% use alcohol, and 23% have used any drugs.

^{Fahrenkopf et al. (2008)} reported that mental disorders affect job performance because concentration capacity decreases (residents with depression have up to 70% difficulty in concentration compared to 38% of residents without depression). Burnout was also common among resident physicians and was associated with self-reported suboptimal patient care practices (^{Shanafelt, Bradley, Wipf, & Back, 2002}).

In a study about depression over an academic year, it was observed that residentes with depressive disorder had a personal history of depression (^{Jiménez-López, Arenas-Osuna, & Angeles-Garay, 2015}).

Although mental disorders and physical discomfort from the academic and work burden of residency have been extensively studied, their association has only been superficially investigated. The aim of this study is to know the association of depression and anxiety with characteristics related to the training of medical residents.

Method

Results

Demographic and clinical data are displayed in Table 1. Subjects were predominantly single (79.33%) and presented anxiety (41.69%). Regarding substance consumption: 70 (12.91%) reported risky alcohol consumption, 3 (.55%) harmful consumption, 404 (74.72%) risk-free consumption, and 65 (11.99%) did not consume; 66 (12.17%) used tobacco without dependence, 45 (9.95%) with low dependency, 2 (.36%) with moderate dependence, and 429 (79.15%) reported not smoking; 75 (13.83%) reported drug use more than a year ago, and an equal number in the last year, 392 (72.32%) did not consume; the rest of the training-related features are listed in Table 2 

When analyzing by grade of residence and kind of specialty, working hours without guard and sleeping hours without guard, it was observed that the surgical specialties were those with longer working hours and less sleep hours. The prevalence of major depression and generalized anxiety disorder was 12.2% (95% CI [9.33, 15.02]) and 41.7% (95% CI [37.45, 45.94]), respectively. Regarding the consumption of substances, 80% consumed alcohol, 20.9% consumed tobacco, and 27.6% had used drugs.

When performing the bivariate analysis for depression, the characteristics with the greatest risk were: present daily work fatigue, ORP 26.83 (95% CI [6.58, 109.41], p < .001), daily emotional exhaustion, ORP 9.81 (95% CI [4.76, 20.21], p < .001), decrease in work functioning by not sleeping well, ORP 10.12 (95% CI [3.22, 31.80], p < .001), personal history of depression and/or anxiety, ORP 3.74 (95% CI [2.20, 6.40], p < .001), and being in the 1st grade of residence, ORP 3.71 (95% CI [1.07, 12.84], p = .02). For anxiety, the characteristics of the highest risks are: daily emotional exhaustion, ORP 5.09 (95% CI [3.57, 7.28], p < .001), work fatigue every day, ORP 5.26 (95% CI [3.50, 7.90], p < .001), decrease in work functioning by not sleeping well, ORP 3.81 (95% CI [2.26, 6.44], p < .001), personal history of depression and/or anxiety, ORP 2.72 (95% CI [1.80, 4.11], p < .001), and harmful alcohol consumption, ORP 2.70 (95% CI [1.09, 6.70], p < .001) (Table 3).

In the analysis of the association of residence characteristics and disorders studied, depression and anxiety were found to have a higher association with ABC guard, ORP 1.13 (95% CI [.50, 2.50]) and ORP 1.42 (95% CI [.93, 2.17]), respectively. For tobacco use, a greater association was found with depression and anxiety when consumption was low dependence with ORP 2.70 (95% CI [1.58, 4.60]) and ORP 1.45 (95% CI [1.08, 1.92]), respectively.

Finally, multivariate analysis shows that work fatigue increases the risk of depression or anxiety more than five times, and that the presence of one of the disorders increases the risk of the other more than seven times (Table 4).

Discussion and conclusion

Although reports of emotional distress related to medical work date back to approximately 50 years ago, research in training doctors is relatively recent. The manifestations studied range from stress and burnout to mental disorders and suicide as the most important complication (^{Mata et al., 2015}).

The reasons of the high frequency of mental disorders in medical residents are a matter of debate. In some reports, they are attributed to the characteristics of medical residence; in others to the predisposition for mental disorder (^{Center et al., 2003}). Our results confirm that some characteristics inherent to residence (work fatigue, emotional exhaustion, decrease in work functioning by not sleeping well, personal history of mental disorder, and harmful alcohol and tobacco use) increase the risk of suffering from depression and anxiety. The association with chronic disease is also confirmed.

Finally, it is important to mention that a weakness of the study is that the sample is limited to residents of a High Specialty Medical Unit. However, it is likely that the characteristics inherent to medical residency are very similar at all levels of care. Since our study is cross-sectional, there is temporary ambiguity, so the results must be interpreted with caution. Another important factor is the possibility of having an information bias, since the responses of medical residents may not reflect the situation nowadays. One of the causes is that the questionnaire was not carried out privately and was self-applied, and when incurring in this kind of bias it is not possible to determine the affectation of the risk, since it can be overestimated or underestimated.

However, all in all the strengths of our study were that we used an instrument to diagnose mental disorders rather than to measure symptoms, in addition to adding scales in the case of substance use-abuse (alcohol and tobacco). Medical residents of 32 specialties were included (medical, medical-surgical, and surgical) which allows the characteristics of the sample to be heterogeneous compared to other studies. The sample inquired about other characteristics of the residence (type of guard, hours of workday, labor fatigue, emotional exhaustion) that have not been described in similar studies. Also, the sample size was higher than other studies conducted in our country in this type of population.

Because depression and anxiety associated with training-related characteristics in resident physicians are prevalent, scrutiny of such problems is recommended in order to implement interventions that mitigate discomfort and prevent poor patient care.