The personality traits with depression and suicidal ideation among Thai medical students: a university-based … – BMC Psychology

From this study result, the prevalence of MDD and SI among Thai medical students was 27.4% and 15.9%, respectively. This research identified statistically significant differences in personality traits, regarding the traits of Neuroticism, Extraversion, Agreeableness, and Conscientiousness between the medical students with MDD/SI and those without MDD/SI. The medical students who reported MDD/SI had a higher score on Neuroticism, but a lower score on Extraversion, Agreeableness, and Conscientiousness domain. A higher Neuroticism score was associated with an increment in the odds of MDD. While the increment of the Conscientiousness score was associated with a reduction in the odds of MDD. SI significantly increased with the Neuroticism score and by having a psychiatric illness.

The prevalence of MDD among medical students in this study was in line with the prior meta-analysis, which reported a global prevalence of MDD among medical students of 28.0% [24]. This prevalence rate was still higher than the general population [1]. However, the prevalence of SI, identified in our study, was higher than before. Previously, the reported prevalence of SI among medical students in Brazil [12] and Northern Thailand [9] was 7.2% and 12.5%, respectively. Because SI was one of the leading causes of death among medical students [12], this finding raises our awareness that MDD and SI among medical students should deserve special attention. Moreover, our study found that 22 (64.7%) participants, who had a history of MDD or dysthymia, reported still having symptoms of MDD by PHQ-9 score. A possible explanation for this finding could be that they did not receive treatment, received inadequate treatment, or despite receiving treatment they had residual symptoms of MDD [25, 26]. Thus, this issue should be brought to the attention of medical schools and health authorities. All parties involved should offer early detection and set prevention programs, and interventions for MDD and SI among medical students before graduation.

Personality traits accessed by IPIP-NEO have been studied for a long time in patients with psychiatric illnesses. The most consistent finding was that traits of Neuroticism were higher in individuals with MDD [15, 18, 27,28,29]. The meta-analysis in 2010, including 175 studies published from 1980 to 2007, studied individuals with MDD, anxiety, and substance use disorders who reported low Conscientiousness scores and high Neuroticism scores in all diagnostic groups [27]. In 2013 Netherland study in older adults, identified that low Extraversion, and Conscientiousness scores and high Neuroticism scores were significantly associated with the presence and severity of MDD [28]. In a more detailed study in the USA in 2013, investigating the facets of each personality domain, the study reported that MDD was related to lower Extraversion (and facets of activeness, assertiveness, and positive emotionality) and Conscientiousness (and facets of competence, dutifulness, order, and self-discipline) and higher Neuroticism (and all its facets; anxiety, depressiveness, hostility, impulsivity, self-consciousness, and stress-vulnerability) [29]. The result of such personality profiles in individuals with MDD showed consistency across cultures. In a Japanese study, in 2013, individuals with treatment-resistant MDD showed a low score of Extraversion, Openness, and Conscientiousness, and a high score of Neuroticism [15].

In Thailand, 2023, regarding the IPIP-NEO Thai version, the study showed that individuals with MDD scored lower on the Extraversion and Conscientiousness domains, and higher on the Neuroticism domain [18]. Our study was done in a specific population of medical students. Similarly, the finding was congruent with the previous studies. We found statistical differences in personality traits between medical students with MDD and those without MDD. The medical students with MDD had significantly lower Extraversion and Conscientiousness scores and higher Neuroticism scores. Additionally, Openness domains were not associated with MDD. This finding was also similar to the prior study [28, 29]. As the Openness domain was related to inventiveness, and curiosity [20]. A possible explanation for this finding could be that the presence of MDD may not affect inventive, and curious behavior. Another explanation is the sample size in this study may not be enough to detect such an association.

Trying to identify the association between personality traits and SI, this study showed the same association reported in MDD. A possible explanation for this result could be that the symptoms of MDD and SI might be the same issue. In addition, a higher Neuroticism score and having a psychiatric illness were associated with SI. This is the same as the prior study that reported a higher score of Neuroticism was associated with greater odds of suicide attempts [17]. Therefore, the Neuroticism domain may be used as one predictor of risk for SI. Moreover, this study identified having a psychiatric illness was associated with SI. A possible explanation for this finding could be that half of these medical students were MDD/dysthymia and they may receive inadequate antidepressant treatment. This may cause the presence of residual symptoms; including SI. Therefore, among medical students with a history of psychiatric disorders, special attention should be given to thoughts of self-harm; as this is considered a risk to life.

The result from this study cannot be concluded in a cause-effect fashion due to the cross-sectional study design. In the prior study using Mendelian Randomization (MR) to investigate causal relationships, the result identified strong evidence that the trait of Neuroticism is a causal risk factor for MDD. A reduction of the Neuroticism score by 4 points reduces the chance of MDD by about 25.0% [30]. Other evidence indirectly favoring the causal relationship between personality traits and MDD may be that even after remission from MDD, personality traits tended to be well preserved [31, 32]. Therefore, assessment of personality traits might help identify medical students who are potentially more prone to develop MDD in the future and can be prevented by providing early preventative interventions.

Personality traits were linked to coping mechanisms one used when facing life challenges or stressors. Neuroticism was highly related to escape-avoidant coping, Agreeableness was negatively related to confronted coping, and Conscientiousness was related to problem-solving and negatively related to escape avoidance. Additionally, a lower score of Conscientiousness and a higher score of Neuroticism were associated with the presence of residual depressive symptoms in treated individuals with MDD [18]. This information may help us understand some individuals with MDD/dysthymia in our study who still had depressive symptoms despite receiving adequate pharmacological treatment. Apart from pointing out the population at risk for developing MDD, knowing personality traits can guide us to the underlying coping mechanism and target improving the immature coping mechanism for better treatment outcomes. For the Faculty of Medicine policy, establishing a personality traits assessment may assist in the medical student entrance examination process to identify who is more prone to develop MDD. Additionally, providing early preventative intervention programs to make medical students aware of their personality traits or coping mechanisms may help them find more adaptive coping mechanisms and areas for self-development. These processes may reduce the chance of MDD among them in the future.

The study of personality traits in Thailand was still limited. In Thailand, this was the first one which had conducted for medical students. We tried to enroll subjects from all regions of Thailand, but by convenience collecting process, the sample size had no equal probability of providing a sample in each region. The population was dominated by the Southern institutions. The response rate was 70.9% of medical students who were members of medical student’s official social media. So, this dataset might not fairly represent Thai medical students countrywide. Due to its cross-sectional design, the result could only provide association but not cause-and-effect interpretation and was limited in its ability to infer causality. Therefore, future longitudinal research to explore causality would be valuable. Another limitation was the use of self-administered questionnaires which can be misunderstood regarding the intended meaning of the questions. We minimized this problem by choosing the questionnaires with good reliability or good Cronbach’s alpha coefficient. However, the notably low Cronbach’s alpha of 0.37 for the Agreeableness domain suggested that this domain might not be reliably assessed with the IPIP-NEO Thai version. This could affect the interpretation of results related to the Agreeableness domain. However, for the data in this study, Cronbach’s alpha coefficient of 0.79 for the Agreeableness domain suggested that this tool is reasonably reliable. In addition, the online questionnaire method was efficient and could reach a wide audience but might introduce bias, as it might exclude those without internet access or those less inclined to participate in online surveys or include those more have a particular interest in mental health. Therefore, future studies could address these limitations, perhaps through stratified sampling or more multi-center collaboration, which would be valuable.

Further studies in this field should be conducted in a longitudinal design to investigate the temporal relationship between personality traits and MDD. Other psychiatric diagnoses are also interesting to be explored about personality traits. The coping mechanism is the other issue concerning personality traits. In addition, cultural factors might influence the expression of personality traits and their association with mental health outcomes. So, a deeper examination of how cultural factors affected them, may need further understanding.