Our results show that the majority of mental problems detected in volunteers by the PHI scale were depression, hypomania, and psychopathic deviance. The UNR subscale had the highest rate of detection of severe mental problems. The total detection rate for psychological disorders detected by the OQ-45 scale was low among university volunteers. As expected, we found a significant correlation between personality traits and mental symptoms of university volunteers. Volunteers with the personality traits of somatization, depression, anxiety, psychopathic deviance, or unrealistic nature were more likely to develop mental symptoms with respect to symptom distress, interpersonal relationships, and social roles. However, volunteers with traits of hypochondria were less likely to develop mental problems.
We found that university volunteers tended to report a better mood than the general population. Nearly 1.4% of volunteers were diagnosed with mental disorders, and the predominant personality trait observed in volunteers was hypomania. Scores on the hypomania scale were significantly higher among university volunteers than the general population. According to the results of WHO World Mental Health Surveys [23], 1.9% of university students were considered to have mental disorders, the vast majority of which included mania/hypomania (77.9%). Hypomania occurs among individuals between 15 and 24 years old and co-occurs with depressive symptoms [24]. University students with hypomania were characterized as hyperactive, optimistic, and prone to overestimating themselves. Hence, the elevated hypomania scores seen in our study could be associated with unrealistically positive self-appraisal, over-activity, and low self-control [25]. We conclude that personality traits can be useful indices for the screening and prevention of mental problems in university volunteers.
In general, we found that personality traits can predict the occurrence of mental symptoms among volunteers. In particular, we found that the traits of anxiety and depression were major predictors of susceptibility to mental symptoms. Our results were comparable to those of previous research, showing a good concordance between personality traits and psychiatry [26-28]. A previous study [29] reported that individuals with personality disorders had poorer outcomes for depression treatment than those with no personality disorders (OR = 2.16, CI = 1.83–2.56). Robison E.J. et al. [30] found that personality traits have unique associations with chronicity and an earlier onset of depression, and these associations remained the same over time. The precise mechanism of this phenomenon remains unclear, reflecting our incomplete knowledge of the biology underlying personality traits’ impact on mental symptoms. However, a previous cohort study on neuroendocrine [31] found that personality traits are associated with hypothalamic-pituitary-adrenal (HPA) axis functioning among adolescents. Baseline cortisol levels are related to facets of several personality traits, including neuroticism, extraversion, and conscientiousness. Hence, we suggest that personality traits might stably influence the occurrence of mental symptoms among volunteers through alteration of the HPA axis.
In particular, we found a strong independent association between the trait of anxiety and mental symptoms. Our results were similar to those of a previous study [32] and support the association of anxiety traits with the emotional anxiety experience [33]. A recent study [34] found that anxiety traits could lead to prolonged HPA hyperactivity. In other words, volunteers with anxious personalities might be prone to developing a variety of stress-induced psychopathologies. However, the etiology of anxiety is very complex [35]. Both genetic variants and environmental factors have been associated with anxiety disorders [36]. The molecular alterations in individuals’ brains, including changes to neurotransmitters, neuroendocrine factors, and mitochondrial function, might explain symptoms of distress in individuals with high anxiety [37]. Oxidative stress also contributes to the etiology of mental symptoms related to anxiety [38]. A recent study [39] characterized the molecular underpinnings of anxiety and identified changes to mitochondrial pathways, oxidative phosphorylation, and oxidative stress. An animal study [40] indicated that reactive oxygen species can affect anxiety in animals by altering oxidative stress in the brain. Controversially, anxiety-like behaviors can be attenuated by inhibition of NOX2-derived oxidative stress [41]. Oxidative stress might serve to bridge the pathophysiological gap between anxiety and various diseases, including psychiatric illnesses [42]. Hence, we suggest that there might be a relationship between oxidative stress metabolism and the genesis of anxiety traits, ultimately resulting in the occurrence of symptoms of distress and poor social adaptability.
As a sub-trait of neuroticism, we also found that the trait of depression was moderately correlated with mental symptoms, consistent with a previous study [32]. Current evidence provides tentative insights regarding the association between depression and mental symptoms. First, it has been well-documented that depression is associated with poor interpersonal communication [43]. Traits of depression, combined with emotional stress from academic difficulties and interpersonal relationships, might increase risk of mental symptoms among volunteers. An animal model [44] found that early-stage stress could influence maturation of the HPA axis, while later-stage stress could lead to problems with interpersonal and social relationships. Hence, distress and dissatisfaction with interpersonal relationships and social roles could reflect internal psychological problems, such as depression, among volunteers. Secondly, we found that depression was associated with symptoms of distress, including symptoms of depression and anxiety, consistent with previous studies[45]. Van H. L. et al. [46] found that individuals with personality disorders have a much higher risk of depression symptoms than the general population. Gene polymorphisms, such as retinoid-related orphan receptor alpha (RORA) gene variation, might contribute to genetic susceptibility to depression [47]. Overall, the occurrence of mental symptoms probably reflects additional underlying psychological factors, such as those about an individual’s personality [48].
In summary, the main findings of our study are the associations between personality traits and mental symptoms. To our knowledge, this the first study to investigate these associations among a large sample of university volunteers in China. Furthermore, we were able to screen out some volunteers with mental problems, although they accounted for a small proportion of total volunteers. Identification of volunteers predisposed to mental symptoms might allow more effective implementation of early prevention programs. There were also some limitations to our study. First, our conclusions regarding the link between personality traits and mental symptoms remain tentative. There might also be some psychopathology and confounders for which we did not account Second, our study might underestimate the true diagnostic prevalence of mental disorders among volunteers. However, our research is nevertheless valuable as a way to screen for personality disorders and common mental disorders and capture the large majority of cases [49]. Despite these limitations, this is the first study to use a large-scale sample of university volunteers to investigate how personality traits are associated with mental symptoms. Moreover, our study is the first to use the PHI and OQ-45 scales to analyze associations between personality traits and mental symptoms.
We conclude that personality traits might be the antecedent variables of volunteers’ mental symptoms and behaviors. The personality traits of volunteers could reflect their behavioral tendencies with regard to participation in the service of important meetings or games, allowing support for individual guidance of volunteers. These findings highlight the importance of taking personality traits into account when screening mental symptoms among university volunteers for large conferences or national games.