Antidepressant impact in bipolar depression masked by use in severe cases
MedWire News: Antidepressants are frequently used to treat bipolar disorder depression, typically in more severe cases, which may underlie the poorer responses and high rates of mood switching in patients given antidepressants, conclude Spanish scientists.
Despite a long history of usage in bipolar disorder patients with depression, the efficacy and tolerability of antidepressants remains unclear, with recent reviews yielding inconsistent results. Furthermore, the reasons for using antidepressants in such patients are not well understood.
To investigate further, Eduard Vieta, from Hospital Clinic Barcelona, and colleagues studied 290 adult bipolar disorder patients in a major depressive episode, of whom 71.4% had type 1 bipolar disorder and 51.7% were women, following them up for 6 months.
In all, 80.3% of patients received antidepressants, of which the most commonly used medication was a serotonin-reuptake inhibitor. Mood stabilizers were given to 79.8% of patients treated with an antidepressant and to 78.6% of those treated without.
On multivariate logistic regression analysis, factors independently and significantly associated with antidepressant treatment were increasing duration of illness, number of depressive episodes per year, depressive first-lifetime episode, melancholic current episode, and less affective illness among first-degree relatives, at odds ratios of 1.13, 37.2, 5.05, 5.84, and 2.42, respectively.
By 8 weeks, just 64.4% of antidepressant-treated patients experienced a treatment response, defined as 50% or greater recovery, compared with 82.1% of controls. Patients not given antidepressants were less likely to experience a mood switch than treated patients (78.6 vs 38.6%).
Writing in the Journal of Affective Disorders, the researchers conclude: "Additional effort is required to identify safe and effective methods of treating bipolar depression, of recognizing and appropriately treating bipolar disorder earlier, to clarify the protective effect of specific mood-stabilizers and doses against mood-switching with antidepressants, and to resolve the question of possible differences in antidepressant-responses in specific types of mood disorders."
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By Liam Davenport