Participants were 47 physically and mentally healthy students. Their profile is shown in Table 1. Participants had attended a class in acquiring proficiency in defensive functioning level. Written informed consent was obtained from all subjects and the study was approved by the institutional review board of Niigata University.

Defensive Functioning Scale. We used the Defensive Functioning Scale, described in “Appendix B of Criteria sets and axes provided for further study of DSM-IV” to measure participants’ level of defensive functioning [3] (Table 2). The scale requires participants to list up to seven defense mechanisms starting with the most prominent; each defense mechanism is grouped under seven Defense Levels (see Table 2). Each participants’ scores on the seven Defense Levels were summed from a possible total of 840 points as follows: High adaptive level (30 points), Mental inhibitions level (25 points), Minor image-distorting level (20 points), Disavowal level (15 points), Major image-distorting level (10 points), Action level (5 points), and Level of defensive dysregulation (0 points). This method of quantification is our original because it is invented by our team.

Cornell Medical Index (CMI). The CMI was developed in the US and is used worldwide for diagnosis and patient care at the bedside [4] -[8] . With the addition of some local questions, this test has been widely used for more than half a century in Japan. It was devised to meet the need to collect a large body of pertinent medical and psychiatric data with minimal time expenditure. It consists of two categories: physical symptoms (including past illness and family history) and mental symptoms (behavior, mood, or feeling). There are 12 sections measuring physical symptoms (A-L) and 6 sections measuring mental symptoms (M-R) as shown in Table 3.

The relationships between defensive functioning and physical symptoms, defensive functioning and mental

symptoms, and physical symptoms and mental symptoms were examined to investigate the developmental level of defensive functioning and adaptive state. Regression analyses were conducted using statistical software Statcel 2 (OMS Publishing, Saitama, Japan), which is written in Visual Basic for Applications. The Mann-Whitney U test was performed using IBM SPSS Statistics for Windows version 20.0 (Armonk, NY: IBM Corp.). Means (±standard deviations) were calculated to compare male and female groups. All statistical tests were two-tailed and statistical significance was defined as P < 0.05.

Means and standard deviations for scores on the defensive functioning scale, physical symptoms, and mental symptoms are shown in Table 4.

The relationships between defensive functioning and physical symptoms, and between defensive functioning and mental symptoms, were examined. Males scored higher than females on defensive functioning and physical symptoms, although the differences were not statistically significant (P = 0.91, P = 0.51, respectively). This may be because of the considerable individual variability in these scores.

For males, there was a positive correlation between defensive functioning and physical symptoms, and between defensive functioning and mental symptoms; however, these relationships were negative for females (Figure 1(a), Figure 1(b)). There was also a notable difference in the average of physical symptoms scores. Females scored higher than males by 2 points on section H of the CMI (genitourinary system). However, the overall average CMI score for males was higher than that of females (15.5 ± 7.8 compared to 14.8 ± 6.1).

Correlations between physical symptoms and mental symptoms were positive and relatively high for both males and females (r [R²]: 0.74 [0.5485] and 0.77 [0.5969]) (Figure 1(c)).

Defense mechanisms are automatic psychological processes that protect the individual against anxiety and from the awareness of internal or external dangers or stressors. Individuals are often unaware of these processes as they operate. Defense mechanisms mediate the individual’s reaction to emotional conflicts and to internal and external stressors. Individual defense mechanisms are divided conceptually and empirically into related groups that are referred to as Defense Levels [3] .

The results of this study showed that participants’ developmental level of mental defensive functioning was quite sound (males [683.8 ± 140.3]/810, females [653.9 ± 85.3]/810). This suggests that the personality structure has almost completely developed by 18 - 20 years old.

Although the differences were not statistically significant, it was of interest that males’ average scores on the Defensive Functioning Scale, physical symptoms and mental symptoms were higher than females’. This may be a result of the social and cultural background in Japan, which has led to the suppression of women’s social status. For modern Japanese women, physical and mental patience is considered a virtue [9] .

A pertinent example is the ratio of female administrative service workers above the level of division chief in Japan. This is a mere 11.1%, whereas the same figures in America and France are 43.1% and 39.4%, respectively [10] . Even in modern times, young females may be unduly influenced by this traditional attitude and may consciously―or unconsciously―suppress their thoughts and feelings even when experiencing physical or mental stress.

For both males and females, there was a relatively high correlation between physical symptoms and mental symptoms; this psychosomatic correlation suggests an adaptive response. Therefore, university health administrative staff need to provide both physical and mental care to help students manage stress effectively. However, larger, comparative studies exploring the social and cultural background of other countries are needed to add support to these conclusions.