| Summary: | 碩士 === 中原大學 === 心理學研究所 === 101 === Background: Reports of negative correlation between major depressive disorder and osteoporosis have been continuously filed since its discovery more than twenty years ago. Taking the effects of ages, drugs, and living style into consideration, multiple reports have shown that depression is a potential risk factor to bone loss. As females become older, they are more susceptible to physical risk factors than males, because decreasing level of hormone makes females have lesser physical protection than males. Besides, females are more sensitive and have a more reactive emotion characteristic compares to males. Based on the above two main reasons, it would be interesting to study the correlation between associated-pathways and depression-induced osteoporosis when focus on females with specific vulnerabilities. Our main hypothesis is that depressive clients have a dysfunction of autonomic nerve system which leads to bone loss. Therefore, we will study the association between depressive symptoms and bone mineral density. Lastly, we will also look into the role that autonomic nerve system plays between depressive symptoms and the stress psychophysiological reactivities of autonomic nervous system (e.g. breathing amplitude, skin conductance, temperature, and heart rate variability related indices).
Method: This study is a 2×3 experimental design (group × situation). Inter-variable includes depressed and non-depressed group. Intra-variables include three experimental phases: baseline, stress, and recovery phase. 53 female participants went through three experimental procedures and their psychophysiological reactivities were recorded by the biofeedback machine (ProComp InfiniteTM). Self-reporting scales and DXA examination are also acquired after every participant has signed up the inform consent for all the study protocols. F test and Pearson’s r are statistical methods we used to examine the difference between groups, and to find out the degree of the association between two variables, respectively.
Result: Compared to non-depressed group, depressed group showed significantly lower values in lumbar bone mineral density (BMD), left hip T-score and left hip Z-score. The correlation between depressive symptoms and some of the bone mineral density indices showed significant negativity within all participants, especially with some lumbar BMD indices. We have testified that different phases exert certain reversible effects on the participants’ autonomic regulations that aligned with our hypothesis. Even though there was no significant difference showed up between two groups, we found seven out of twelve psychophysiological indices were significantly related to bone values, and eight indices were borderline significantly related on the other hand. Also, within frequency domain heart rate variability (HRV) indices, nine out of twelve indices were significantly related to left hip BMD, T-score, and Z-score.
Discussion: Even though the females in this study were younger than those usual high risk osteoporotic groups are, the results still demonstrated the relationship between major depressive disorder and BMD. In particular, the correlation was significantly negative between psychophysiological indices and BMD regardless of some limitations such as, sample size and unstandardized experimental environment. Notably, our study have two main findings, first, females with major depressive disorder might have a certain possibility about the dysfunction regulation of sympathovagal nerves. Still, among all psychophysiological indices examined, skin conductance, LF, LF/HF are highly correlated with different BMD values. However, whether depression-induced osteoporosis is mediated by autonomic nervous system and what route is involved are issues in need of further investigation.
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