First-episode type predicts morbidity, disease course in bipolar disorder

By Ingrid Grasmo, medwireNews Reporter

Study findings suggest that the type of first episode in patients with bipolar disorder can predict the type and degree of future morbidity, as well as the disease course.

Analysis of clinical records and life charts from 1081 patients diagnosed with bipolar disorder in Italy who were followed up for an average of 15.7 years showed that depression was the most common presentation for a first episode (58.9%), followed by mania (13.4%), psychosis (8.0%), anxiety (7.6%), hypomania (6.7%), and mixed states (5.5%).

A first episode characterized by initial depression, anxiety or mixed states was associated with later depression, suicidal thoughts or acts, and antidepressant treatment. Conversely, initial presentations of mania or psychosis predicted future episodes of mania.

Notably, the study showed that initial depressive episodes were significantly more common in bipolar disorder-II than in bipolar disorder-I patients (77.5% vs 46.4%).

Ross Baldessarini (McLean Hospital, Belmont, Massachusetts, USA) and colleagues say the findings are consistent with a number of studies showing that the long-term course of bipolar disorder can be more predictable than previously thought.

“Such associations should contribute to formulating earlier and more reliable prognosis in patients with [bipolar disorder], predicting treatment responses, [and] long-range planning for their clinical care,” they comment in Acta Psychiatrica Scandinavica.

Analysis of demographic factors associated with first episode types revealed that these varied significantly among onset types, showing significant differences in gender, family history, education, employment, and marriage status.

Clinical characteristics were also significantly different among onset types, with the mania or hypomania–depression–euthymia interval (MDI) course pattern most commonly observed (34.4%) compared with depression before mania (DMI; 25.0%).

MDI course patterns were significantly associated with psychotic or manic onset, while DMI patterns most often followed anxiety (38.8%), depression (30.8%), or mixed onsets (13.3%).

To clarify comparisons, the researchers performed multivariate analysis of factors associated with first-episode types. Findings revealed that factors significantly associated with initial depression-related first episodes (depressive, mixed or anxiety) included a DMI > MDI course patterns, more time spent in depression than mania, rapid or continuous cycling, more use of antidepressants, and more suicidal thoughts or actions.

“These factors are consistent with the general prediction of an excess of depressive morbidity,” comment the researchers.

Finally, the study showed that antidepressant treatment was used by 65.4% of patients and was strongly associated with depression and anxiety as onset episodes.

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