Clinical features identified to distinguish bipolar I disorder from MDD

By Lucy Piper, Senior medwireNews Reporter

Researchers have identified seven clinical features that could help distinguish patients with bipolar disorder from those with major depressive disorder (MDD).

“[O]ur result may have sufficient accuracy to be relevant for clinical use”, say researcher Fernando Goes (Johns Hopkins School Of Medicine, Baltimore, Maryland, USA) and colleagues.

However, the distinction was primarily for bipolar I disorder, with only subtle differences seen between bipolar II disorder and MDD.

The seven features, which were found to be associated with bipolar I disorder when 386 patients with the condition were compared with 684 with MDD in an original dataset, remained significant after multiple logistic regression.

The strongest of these was a history of experiencing a high after antidepressant treatment, followed by delusions, psychomotor retardation, incapacitation, greater number of mixed symptoms, greater number of episodes and shorter episode length.

Receiver operating characteristic analyses showed that these seven features were very good at differentiating between bipolar I disorder and MDD, with an area under the curve of 0.84. This was echoed in an independent dataset of 1000 patients with bipolar I disorder and 1000 with MDD.

Under optimal conditions, the clinical features would have a sensitivity of 76% and a specificity of 78%, the researchers report in Psychological Medicine.

There were only two features distinguishing the 158 patients with bipolar II disorder from those with MDD; an increased number of mixed symptoms and feeling high after antidepressant treatment.

The researchers say that their study indicates that “clinical features continue to have important classification potential that should not be ignored”.

They recommend that “these features should be integrated with biological markers in future studies aiming to predict diagnosis and course of illness.”

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