Many depressive patients fall into ‘soft bipolar spectrum’
MedWire News: Around 85% of patients who present with depression may show some degree of bipolarity based on the concept of the soft bipolar spectrum, study results show.
The researchers also claim to have validated the diagnostic entities of bipolar II1/2 and IV disorder using the predictive value of temperament profiles.
"Most bipolar disorder patients are 'hidden' - not diagnosed at all or falsely diagnosed as suffering from unipolar disorder," say Takeshi Terao and colleagues from the Oita University Faculty of Medicine in Yufu city, Japan, reporting in the Journal of Affective Disorders.
Because many patients present with depression, the identification of a hypomania is difficult because it has "generally not been experienced as a morbid event but rather as a favorable egosyntonic episode," the researchers note.
In the current study, Terao et al re-assessed 46 consecutive patients who initially presented with symptoms of depression. Their initial DSM diagnoses were bipolar I disorder (n=1), bipolar II disorder (n=9), major depressive disorder (n=34), and depressive disorder not otherwise specified (n=2). The minimum treatment duration for inclusion in the study was 3 months.
At re-assessment the patients were asked to fill out the Japanese version of Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Auto questionnaire (TEMPS-A).
Of the 46 patients, 31 exhibited depressive temperament, 33 cyclothymic temperament, 14 hyperthymic temperament, 24 irritable temperament, and 24 anxious temperament.
Thus, there was considerable overlap between temperaments. Patients who had both depressive with cyclothymic temperament met the tentative, operational criteria for bipolar II1/2 (n=32), while those who had depressive and hyperthymic temperament met the criteria for bipolar IV.
Based on the "soft bipolar spectrum" of bipolar disorder II, II1/2, and IV, then 39 (85%) patients fell into this bracket, the researchers note.
They also found that soft bipolar spectrum patients receiving lithium treatment were significantly more likely to be in remission than those not receiving lithium. In addition, more of those taking selective serotonin reuptake inhibitors (SSRIs) had a significant tendency to lower remission rates than those not taking SSRIs.
"The present findings suggest that cyclothymic and hyperthymic temperaments may predict bipolarity, and the validity of bipolar II1/2 and IV concept is supported," Terao and colleagues comment.
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By Andrew Czyzewski