History of bipolar disorder affects illness characteristics and outcomes
MedWire News: Bipolar disorder patients experiencing their first acute mania episode present with different illness characteristics and achieve recovery and remission more quickly than patients with multiple episodes, findings from the EMBLEM study show.
First-episode patients were significantly younger, had a lower body mass index, and a higher incidence of past or current cannabis abuse than multiple-episode patients.
First-episode patients also had, on average, significantly higher baseline Young Mania Rating Scale (YMRS) total and Clinical Global Impressions-Bipolar Disorder (CGI-BP) mania scores, compared with multiple-episode patients (28.5 vs 26.3 and 5.0 vs 4.8, respectively).
The researchers note, however, that while first-episode patients had greater illness severity than multiple-episode patients, the latter patients had greater functional impairment, based on self-reports.
They also had higher levels of baseline depressive symptoms than first-episode patients, according to CGI-BP depression and Hamilton Depression Rating Scale total scores.
Mauricio Tohen, from the University of Texas Health Science Center at San Antonio, USA, and colleagues therefore suggest that “the level of functional impairment may not be directly related to the symptomatic severity of the index manic episode but, rather, reflect the extent of prior illness course.”
Of 3115 patients enrolled in the EMBLEM (European Mania in Bipolar Longitudinal Evaluation of Medication) study, 256 presented with a first manic or mixed episode while the remaining patients had previously experienced manic or mixed episodes. All the patients had a CGI-BP mania score of at least 3.
In addition to determining differences in illness characteristics between first- and multiple-episode patients at baseline, the researchers compared the two groups with regard to recovery and remission after 12 weeks of antipsychotic treatment.
A significantly greater percentage of patients in the first-episode group than in the multiple-episode group met the criteria for recovery at the 12-week endpoint (CGI-BP overall score of 2 or below at endpoint), at 39.6% versus 33.1%, respectively. Recovery also occurred more quickly in first-episode than multiple-episode patients.
Significant differences in rates of remission were also seen at the 12-week endpoint, at 80.4% for single-episode patients versus 69.0% for multiple-episode patients, and times to remission were shorter for first-episode patients.
“These findings highlight important distinctions in illness characteristics, outcome and possibly treatment response between patients at different points in the longitudinal course of bipolar disorder,” Tohen et al write in the Journal of Clinical Psychiatry.
They therefore recommend consideration of the longitudinal dimension of bipolar disorder in the determination of prognosis and treatment strategies.
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By Lucy Piper