The purpose of this study is to contribute to the knowledge of the clinical characteristics of the bipolar spectrum by examining factors associated to course of symptoms in BP patients. We evaluated differences between acutely depressed versus subthreshold mixed patients.

90 depressed patients (Group 1, HDRS: 18.2±4.6, YMRS: 1.4±2.9) and 41 patients presenting a mixed subthreshold symptomathology (Group 2, HDRS: 9.1±3.2, YMRS: 9.6±6.4) were included in the study. All patients underwent structured diagnostic interviews for axis I and axis II disorders (SCID-I, SCID-II) and have been submitted to psychometric assessment with Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS), Young Mania Rating Scale (YMRS), Global Assessment Scale (GAS), Social Adjustment Self-reported Scale (SASS), Quality of Life Scale (QoL), at baseline and repeated follow-up (1, 3, 6, 12 months). Personality dimensions were evaluated by Temperament and Character Inventory (TCI-R).

The most important result is the slight increase in depressive symptoms in subthreshold mixed patients after 3 months of treatment. These patients were more likely diagnosed as BP-I, were non-SUD patients and/or non-comorbid for axis II personality disorders and had a shorter duration of current episode prior intake. Measures of social and functional adjustment were not different in the two groups, though a slight trend for depressed patients to report a poorer quality of life. No difference in personality traits were observed among the two samples.

Our study confirms the importance of considering subthreshold symptoms in the evaluation and treatment of patients with Bipolar Disorder.