Magazine article Clinical Psychiatry News

Neuroimaging as Tool for Diagnosis, Treatment in Sight: Identifying Bipolar Disorder Is a Priority

Magazine article Clinical Psychiatry News

Neuroimaging as Tool for Diagnosis, Treatment in Sight: Identifying Bipolar Disorder Is a Priority

Article excerpt

PITTSBURGH -- Neuroimaging may soon become an important clinical tool for the diagnosis and treatment of mood disorders, Dr. Mary L. Phillips said at the Seventh International Conference on Bipolar Disorder.

Emerging data suggest that functional magnetic resonance imaging (fMRI) can identify specific neural biomarkers that may help distinguish patients with bipolar disorder from those with unipolar disorder. These data may also help physicians assess which patients will respond to which psychotropic medications and possibly even predict which healthy individuals at high genetic risk will go on to develop bipolar disorder, said Dr. Phillips, who is with both the University of Pittsburgh, where she is professor of psychiatry and director of the functional neuroimaging program, and the Institute of Psychiatry in London, where she is with the section of neuroscience and emotion.

"I think neuroimaging is a really interesting, promising technique for the future. We've moved beyond blue sky high-level science for its own sake. We're now using neuroimaging to ask and answer real-life clinical problems," she said at a press briefing held during the conference.

Improving the diagnostic capability of those who treat bipolar disorder is a research priority and is likely to be the first bedside use of the technology. Bipolar disorder is frequently misdiagnosed as unipolar depression, often for as long as 8-10 years, before patients receive a correct diagnosis and treatment. "If we can do anything to speed up the process of diagnosis, it would be a good thing," she remarked.

Using fMRI to record neural responses to pictures of people with facial expressions of varying emotions, Dr. Phillips and her London associates found distinct differences between a group of 12 patients with a diagnosis of bipolar I disorder, 9 with major depressive disorder, and 11 healthy control subjects.

The bipolar group demonstrated increases in both subcortical (ventral, striatal, thalamic, and hippocampal) and ventral prefrontal cortical responses, particularly to expressions of mild and intense fear, mild happiness, and mild sadness; activity was diminished in the dorsal prefrontal cortical area to the majority of facial expressions (Biol. Psychiatry 2004;55:578-87).

The results are in line with the reality that one of the specific subcortical areas that show abnormally elevated activity, the ventral striatum, is associated with the processing of expressions of emotion and reward. Interestingly, activity in this area was most elevated by pictures of faces showing expressions of mild happiness rather than to faces showing more extreme emotions. This may be explained by the fact that mild expressions of happiness are more frequently observed in everyday life, and may be seen as especially rewarding in people with bipolar disorder, Dr. Phillips said in an interview.

The dorsal prefrontal cortical area, where the bipolar patients showed lower brain activity, comprises the regions primarily associated with regulation of emotion. Reduced activity in these regions may therefore underlie the emotional lability experienced by people with bipolar.

In contrast, the group with unipolar depression showed diminished neural responses to all emotional expressions except mild sadness. …

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