medwireNews: Patients with bipolar disorder regulate their emotions differently from those with major depressive disorder (MDD) in both depressed and remitted states, a study shows.
Bipolar disorder patients had impaired emotion regulation even in the remitted state; however, in the depressed state they had “unexpectedly normal” regulation of happy emotions, whereas MDD patients had impaired regulation of both happy and sad emotions, report researcher Maria Rive (University of Amsterdam, the Netherlands) and co-workers.
The patients observed pictures depicting different emotions and either viewed them passively or attempted to distance themselves from the emotion. The 26 remitted bipolar disorder patients were significantly less successful at emotion regulation than the 21 remitted MDD patients and 36 mentally healthy controls, irrespective of whether the emotion was happy or sad.
The patients underwent functional magnetic resonance imaging while attempting emotion regulation, revealing significantly increased activity in the dorsolateral prefrontal cortex of the bipolar patients relative to MDD patients, which the team believes “reflects increased, but still insufficient, regulation attempts” in the bipolar patients.
Among currently depressed patients, the 21 MDD patients had impaired regulation of both sad and happy emotions, relative to controls, whereas the nine bipolar patients had impaired regulation of sad emotions but could successfully distance themselves from happy emotions.
The researchers speculate that the happy pictures provoked happy emotions in the bipolar patients, which were contrary to their mood and thus easy to distance themselves from, whereas they triggered sad emotions in the MDD patients.
“These state-specific emotion regulation differences may represent different underlying pathophysiological mechanisms”, writes the team in JAMA Psychiatry. They suggest that these differences, in combination with clinical features and imaging biomarkers, may help to “resolve remaining diagnostic uncertainty” between bipolar disorder and MDD.
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