本帖最後由 lsc0019 於 2009-7-21 23:21 編輯
作者：Janis Kelly
出處：WebMD醫學新聞
July 1, 2009 — 一項使用神經造影技術的研究已經找出區分初期雙極性精神異常的憂鬱症與重鬱症的不同，且可能可以提早確認出使用精神治療改變疾病進程的高風險病患。
賓州匹茲堡大學情緒異常功能性造影主任與精神學教授Mary L. Phillips博士，在第8屆國際雙極性異常會議中討論到這項影像檢查研究。
Phillips博士向Medscape精神學表示，如果病患以憂鬱症表現，且沒有躁鬱或是興奮病史，雙極性異常經常是不容易診斷的。因為這可能會造成以抗憂鬱藥物進行不適當的治療，且延遲以情緒穩定藥物治療的時程，接著可能會使躁鬱期延長。我們已經知道以功能核磁共振造影（fMRI）進行的神經造影技術可以用來區分重鬱症與雙極性異常的憂鬱症狀。
Phillips博士與其同事們找出與雙極性異常有關的情緒失調區域在杏仁體與眶耳道前額皮質（OMPFC）。當比較被要求標記快樂與悲傷面像情緒強度受試者們的掃描結果，研究者們發現罹患雙極性異常患者，其腦部變化使OMPFC的杏仁體左側調控降低。他們推測，這可能代表情緒高漲與躁鬱。
相對的，罹患重鬱症病患，他們的杏仁體在面對正面情緒刺激時過度調控，這可能造成對正面情緒的反應能力下降。這些受試者們對於負面情緒刺激也有過度的反應。
Phillips博士表示，雙極性憂鬱是雙極性精神異常最常見的表徵，且35%的雙極性異常病患，在症狀發生10年間，並沒有正確的診斷，因此可靠的非侵入性診斷檢查將會有重大的臨床應用。僅有20%的雙極性異常病例，在病患尋求治療的第一年接受正確的診斷。
被診斷罹患雙極性異常病患所生的後代，有同樣異常的風險比一般大眾高出10倍。Phillips博士表示，她的研究團隊目前正在以fMRI檢驗雙極異常病患的後代。
Philips博士指出，我們有數據顯示，特定fMRI異常在除此之外健康的後代上與我們在罹患雙極性異常成人病患身上看到的類似。我們現在追蹤這些兒童，看哪些後來會演變成雙極性異常。如果這些神經顯影標記確實可以找出這些病患，將可以讓我們早期以精神療法介入，且試著介入異常發育途徑，或許可以預防或是降低這些疾病的嚴重度。
Phillips博士與David Axelson與Boris Birmaher博士合作進行這些神經險象研究。
【找出那些處於風險的病患】
Jonathan Savitz醫師向Medscape精神學表示，Phillips博士的發現可能對於研究以及臨床醫師都是非常有用的。
在馬里蘭班賽斯達國家精神健康研究機構的情緒與焦慮異常計劃神經造影部門的Savitz醫師表示，以神經顯影來找出高風險群個體將會是個非常好的進步，因為這將會告訴我們某些有關這個異常的神經病理學，且協助我們了解基因學研究。
作者們表示沒有相關資金上的衝突。
ICBD 2009: fMRI Differentiates Bipolar from Major Depression
By Janis Kelly
Medscape Medical News
July 1, 2009 — A new study using neuroimaging has identified neural system biomarkers that differentiate depression in early bipolar disorder from major depression and might be able to identify "at-risk" children early enough to permit psychotherapy that could alter the course of the disease.
Mary L. Phillips, MD, professor of psychiatry and director of functional neuroimaging in emotional disorders at the University of Pittsburgh School of Medicine, in Pennsylvania, discussed the imaging research at the 8th International Conference on Bipolar Disorder.
"Bipolar disorder is difficult to diagnose if the patient presents with depression and no history of being manic or 'high.' That matters, because it leads to inappropriate treatment with antidepressants and delay in treatment with mood stabilizers, which in turn can make the risk of switching to the manic phase greater," Dr. Phillips told Medscape Psychiatry. "We have shown that neuroimaging with functional magnetic resonance imaging [fMRI] can be used to differentiate major depression from depression in bipolar disorder."
The biomarkers Dr. Phillips and colleagues identified pertain to areas in the amygdala and orbitomeatal prefrontal cortex (OMPFC) involved in the emotional dysregulation associated with bipolar disorder. When they compared scans of subjects who were asked to label the emotional intensity of happy and sad faces, the researchers found that those with bipolar disorder had brain changes that reduced left-sided regulation of the amygdala by OMPFC. This might indicate a predisposition to elevated mood and mania, they speculate.
By contrast, subjects with major depressive disorder had overregulation of the amygdala in response to positive emotional stimuli, which might cause a reduced ability to respond to positive emotions. These subjects also had an exaggerated response to negative emotional stimuli.
Dr. Phillips noted that bipolar depression is the most frequent presentation of bipolar disorder and that 35% of bipolar individuals do not receive a correct diagnosis for more than 10 years after symptoms begin, so a reliable noninvasive diagnostic test would have major clinical implications. Only 20% of bipolar-disorder cases are correctly diagnosed within the first year of the patient seeking treatment.
Children of patients who are diagnosed with bipolar disorder are at 10-fold higher risk for the disorder than the general population. Dr. Phillips said that her research team is now "working backward in time" by using fMRI to examine the offspring of bipolar-disorder patients.
"We have data showing that certain fMRI abnormalities in otherwise-healthy offspring are similar to what we see in adults with bipolar disorder," Dr. Phillips said. "We are now following these children to see which ones go on to develop bipolar disorder. If these neuroimaging markers do identify that subgroup, it might enable us to intervene early with psychotherapy and try to intervene in the abnormal developmental pathway, perhaps preventing or reducing the severity of disease."
Dr. Phillips collaborated on these neuroimaging studies with Drs. David Axelson and Boris Birmaher.
Identifying Those at Risk
Jonathan Savitz, MD, told Medscape Psychiatry that Dr. Phillips's discoveries might be very useful for researchers as well as clinicians.
"The ability to identify high-risk individuals with neuroimaging would be a wonderful advance, because it would tell us something about the underlying neuropathology of the disorder and help?inform genetic studies," said Dr. Savitz, who is in the section on neuroimaging in the Mood and Anxiety Disorders Program at the National Institute of Mental Health, in Bethesda, Maryland.
The authors report no conflict of interest.
8th International Conference on Bipolar Disorder: Abstract 12. Presented June 26, 2009. |
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