Use of one-way ANOVA showed significant differences in all dimensions among the three groups; however, mediating and moderating factors, and any causal effect, have been neglected. The paired group comparison SEMs for the AD
HY, AD–HY, and control groups all revealed a pathway relationship in which parental bonding affected personality characteristics, personality characteristics affected mental health condition, and mental health condition affected the development of hyperventilation or adjustment disorder. More specifically, with respect to parental bonding, males with AD–HY perceived less care from their fathers than those with AD
HY and the controls, and males with AD
HY perceived more maternal protection than those with AD–HY and the controls. Although participants with AD–HY and those with AD
HY were both more neurotic and less extroverted than the controls, those with AD–HY were even more neurotic and less extroverted than those with AD
HY. The two groups with adjustment disorder did not differ in their mental health condition; both showed worse mental health than the controls.
The pathway relationship in which parental bonding affected personality characteristics, which in turn affected mental health condition and the development of hyperventilation syndrome or adjustment disorder, is consistent with previous studies on hyperventilation and adjustment disorders [1
]. Parental emotional neglect is often related to psychiatric disorder [31
]. In addition, the present study found that maternal overprotection increased the risk of hyperventilation syndrome, and less paternal care increased the risk of adjustment disorder. Previous studies have also found that hyperventilation is associated with maternal attachment and premorbid personality [14
]; more specifically, maternal attachment has been found to play a unique role in male adjustment disorder with hyperventilation syndrome [14
]. This can be understood easily, because maternal attachment is related to the development of problems with self-esteem and behavior, particularly maladjustment behavior [1
], and might be linked indirectly to clinical diagnoses of mental health problems [32
Attachment style is an important factor in understanding the particular ways in which individuals feel and react when stressed by illness, and is important when assessing the utilization of healthcare [33
]. With regard to the finding that less paternal care increased the risk of adjustment disorder, previous studies have also found that negative parental attachment is related negatively to the individual’s functional morbidity, such as the inability to cope with daily stress, and problems with adjustment and social skills [35
]. The impact of high parental control and low care tends to increase mental health problems and distress, and such individuals might experience difficulties in interacting with the environment [36
]. Therefore, dysfunctional parenting is one of the main influences on individual personality traits and the ability to adjust [1
]. A previous study found that adolescents who had poor communication with their fathers showed more aggressive behavior toward authority in school and had more difficulty in adjusting [41
]. When these males enter military service, they are within a predominantly male environment, including their superiors. The experience of poor paternal care might be projected onto these superiors, thus augmenting the adjustment problem.
Interestingly, although high neuroticism and low extroversion were found to increase the risk of adjustment disorder or hyperventilation syndrome, individuals with AD–HY showed even greater neuroticism and less extroversion than those with AD
HY. Extroversion had only an indirect effect on individuals with AD
HY when compared with the controls. Several studies have demonstrated that neuroticism and introversion might increase the risk of mental disorders such as anxiety, depression, and maladaptive behaviors [1
]. The present study has highlighted the difference in severity between hyperventilation syndrome and adjustment disorder.
Few studies have investigated the differences between adjustment disorder and hyperventilation syndrome; however, criteria to assist in the differential diagnosis are required. Our study compared individuals with AD–HY, those with AD
HY, and controls, and identified differences among these three groups with respect to parental bonding, personality characteristics, and mental health. Self-report measures were used for the study, which might have resulted in problems of recall bias in terms of the rating of parental attachment, and this could have influenced the results. However, studies have demonstrated that the PBI has acceptable reliability and validity [22
]. Furthermore, participant reports of parental behavior have shown a significant association with independent reports [44
], and twin studies have also shown a high correlation in the rating of parents [45
]. It is thought that attachment insecurity is a determinant of physical health throughout the lifespan [19
]. In the present study, although the PBI was used to measure parental attachment, it does not assess attachment style specifically and this might be a limitation in the current study. Hence, a more in-depth assessment of attachment, using specific self-report questionnaires or the Adult Attachment Interview, should be considered for future studies.