Medical students go through long and intensive academic years in preparation for careers as physicians. There is a growing appreciation of the stress involved in this process. Indeed, previous literature provides hard evidence that a medical school education is highly stressful. One study in England showed that approximately half of the medical students described a stressful incident, the majority of which were related to medical training rather than other problems [1].

Academic load and emotionally challenging work might be associated with psychiatric morbidities in medical students. Studies from different countries revealed that sleep disturbance among medical students is not only common but also its prevalence is higher than in either non-medical students or the general population [2,3]. Several studies have also shown that medical students exhibit more symptoms of depression than the general population [4,5] and depression in first year medical students became twice as prevalent by end of the study period [6]. In addition, reports by Lloyd and Gartrell5 and Vitaliano et al. [6] demonstrate that medical students had greater mean anxiety levels than the norms for the general population.

Stress levels experienced by each student vary, even though they have the same curriculum and various factors to explain this have been suggested. Prior studies have focused on evaluating students’ academic stress, psychiatric problems, motivation, personality traits, coping strategies, and more. For instance, depression [7], academic motivation [8] and academic performance [9] may be related to academic stress, and certain personality traits are associated with motivation [10] and may predict academic performance [11,12]. Another study found that maladaptive emotion-regulating strategies such as catastrophizing, self-blame, and positive reappraisal contribute to academic stress, and motivation was considered as a mediator [13]. In our most recent study, high level of depressive symptom was associated with insomnia, amotivation and academic stress in medical student [14].

Parents in South Korea are renowned for their extraordinary passion toward their children’s academic achievement and university entrance. In general, students who achieve academic excellence can enter medical college in South Korea. Therefore, although not applicable to all, medical students in general tend to have grown up with high expectations from their parents since childhood. Previous literature has shown that parental involvements such as overly valuing children’s achievements, criticism, or affectionless control can be internalized by children and increase the risks of stress, depression, or anxiety [15-18]. However to date, there has been no study that conclusively shows a relationship between academic stress experienced by medical students and parental involvement.

With this background, we hypothesized that medical students’ academic stress would be associated with their psychological health including sleep and mood. Furthermore, the hypothesis of increased susceptibility to academic stress in students who have parents with overprotective parenting style was investigated. The purpose of this study is to gain greater insights into the relationships between various factors associated with academic stress in medical students, such as insomnia, depression, academic motivation, and parental overprotection. Our findings may form the basis for the management of mental health of Korean medical students.

In our study, we found a significant positive association between insomnia and academic stress. Insomnia was a significant variable predicting academic stress in regression analysis. Many studies have indicated that sleep disturbance can either be a comorbidity or a symptom of psychiatric illness [28]. Evidence shows that insomnia can cause subsequent psychiatric disorders like depression and psychiatric distress [14,29]. Moreover, good quality sleep is important for optimal neurocognitive and psychomotor performance [30] and different sleep characteristics influence academic performance [31]. To optimize the mental health of medical students, future research is needed to explore causative factors underlying sleep problems and develop educational programs to improve sleep in medical students.

Parental overprotection was another associated factor in our results. The finding that ‘goal achieving’ and ‘face culture’ score of both parents, respectively, were positively associated with stress level in medical students is interesting and warrants replication. Both subscales were designed as culture-specific constructive domains of Korean parenting when K-POS was originally developed.23 It was highlighted earlier that in contrary to ‘control’ and ‘identification’ which are culture-general and commonly found in Western studies, ‘goal achieving’ and ‘face culture’ are culture-specific factors that reflect more of East Asian values [23]. One possible explanation is that in East Asian contexts, cultural emphasis is often made to recognize connectedness to close others and to fulfill obligation [32]. Reflecting this cultural value, identification and control by parents can be often understood as love and support by children while face-concerning or achievement-oriented parents influence more negatively on the stress level of children. This result suggests that it is important to take into account cultural factors in studying student’s stress.

Depression was also positively correlated with academic stress and was another strong predicting factor in regression analysis, a finding that is in agreement with our recent studies [13]. The existence of a bidirectional relationship between stress exposure and development of depression has long been apparent [33,34]. Our finding also suggests close relatedness between depression and stress level. However, it has to be interpreted cautiously given the cross-sectional design of this study.

Significant correlations between motivation and academic stress were noted in this study. Among types of motivational orientation, amotivation was significantly predictive of stress level according to regression analysis. Such findings are consistent with previous studies which found amotivation was strongly liked to numerous negative outcomes; poor psychosocial adjustment and high levels of perceived stress [13,35]. Based on self-determination theory [36], behaviors are non-regulated and nonintentional for amotivated individuals. With no sense of purpose or expectations of changing events, such individuals are likely to experience feelings of incompetence and uncontrollability, a state similar to that of learned helplessness. Intrinsic motivation has been known to enhance quality of learning, academic performance [36] and general well-being [37]. In this particular sample of students, we observed negative relationship between intrinsic motivation and stress level, although intrinsic motivation was not significant predictor in regression model.

Our study is limited by several factors. First, our assessments were based on self-reporting. However, we do not regard this as a major limitation because all of the instruments we used have been previously validated. Second, we used cross-sectional design, which precludes determination of whether medical stress is causally related to each variable. Future longitudinal studies are warranted to confirm our results. Third, our study sample was from a single center. Whether this sample is representative of all medical students in South Korea with regard to sex, type of medical school and parenting attitude is unknown. Lastly, because instruments which are not only widely accepted but also validated for assessing parental overprotection are scant, K-POS, utilized in the present study, presents its own limitation. The relatively small number of items may have an impact on internal consistency and lack of detectable difference between stressed and non-stressed groups. It is also regrettable that we didn’t analyze female and male students separately, since studies have repeatedly suggested that dysfunctional parenting influences recipients in a gender specific manner [38]. However, to our knowledge, and despite a number of constraints, this study is the first to consider parental overprotection as a relevant measure in contributing to stress levels among medical students.

In sum, our results indicate that academic stress in medical students may be influenced by interaction among various factors including depression, insomnia, motivation and maternal overprotection, especially ‘face culture’. Given the implied relevance of these variables on stress levels in medical students, the question of possible intervention becomes important. The importance of intervention particularly with regard to parenting is raised by our study and future investigation is warranted. We believe that our findings will help guide the configuration of stress management in Korean medical students.