Major Depression May Be Relative of Bipolar Disorder

First, the subjects with recurrent major depression reported that they had experienced a substantial number of manic or hypomanic symptoms over their lifetimes.

“The presence of a significant number of manic/hypomanic items in patients with recurrent major depression seems to challenge the traditional dichotomy of unipolar-bipolar disorder and bridges the gap between these two categories of mood disorders,” the researchers stated in their study report.

Second, in both patients with recurrent major depression and patients with bipolar I disorder, the number of manic/hypomanic items reported was related to the number of depressive items reported, suggesting a link between the two.

And finally, the more manic/hypomanic items that the recurrent major depression subjects reported, the greater the likelihood that they also reported having suicidal ideas or paranoid or delusional thoughts, such as“ feeling as if others were causing all of your problems,”“ feeling surrounded by hostility,” or “everyone is talking about you,” at some point in their lives.

“This latter result,” the researchers wrote,“ corroborates the observation that the presence of even mild manic symptoms may change a depressive presentation into a mixed presentation and increase the likelihood of psychotic symptoms.”

These results imply, said the researchers, that major depression and bipolar disorder are related and that the psychiatric field “would benefit from a unitary and continuous approach to the assessment of both manic/hypomanic and depressive symptoms.”

Or as Cassano told Psychiatric News, the results “provide evidence that a substantial proportion of patients with unipolar depression experience manic/hypomanic symptoms during their lifetime and that these symptoms are associated with a more negative prognosis (suicidality, paranoid ideation). Because this association is similar to the one found in bipolar patients, we conclude that unipolar and bipolar disorders are not two discrete entities, but should be considered a unitary phenomenon, to be studied using a longitudinal perspective.”

When asked about the clinical implications of the results, Cassano said,“ The assessment of manic-hypomanic symptoms in so-called unipolar patients is probably important in predicting a poorer prognosis. A large clinical trial is under way in Pittsburgh and Pisa to determine whether manic/hypomanic symptoms in unipolar patients characterize a distinct phenotype showing a differential response to treatment with SSRI, interpersonal therapy, or a combination of the two.”

David Kupfer, M.D., chair of psychiatry at the University of Pittsburgh and one of the study authors, told Psychiatric News, “The implications of this research for clinical psychiatrists are important since many difficult-to-treat patients are difficult because they have a `dose' of unipolar and bipolar features. While they are often diagnosed with non-bipolar depression, there is a significant degree of subsyndromal lifetime bipolar features that reduce the usual level of therapeutic responsiveness that can be expected with SSRI or other interventions used to treat depression. This may also be true in those individuals who do not respond to targeted psychotherapy alone (interpersonal therapy or cognitive behavioral therapy). Many of these individuals may require treatment sequencing or combination treatments to achieve full recovery.”

The study, “The Mood Spectrum in Unipolar and Bipolar Disorder: Arguments for a Unitary Approach,” is posted online at<http://ajp.psychiatryonline.org/cgi/content/full/161/7/1264>.▪