Antidepressant use associated with subsequent mania diagnosis




Patients with unipolar depression who use antidepressants may increase their risk of subsequently being diagnosed with mania/bipolar disorder, a retrospective cohort study conducted in the United Kingdom showed.

“Our findings demonstrate a significant association between antidepressant therapy in patients with unipolar depression and an increased incidence of mania. This association remained significant after adjusting for age and gender,” wrote Dr. Rashmi Patel of King’s College London and his colleagues.

The study comprised 21,012 adults who were diagnosed with depression and were receiving secondary mental health care for unipolar depression between April 1, 2006, and March 31, 2013. The researchers used electronic health records to determine which patients had used antidepressants prior to being diagnosed with depression and were subsequently diagnosed with mania or bipolar disorder, as well as the dates of the patients’ diagnoses. Patients were followed up to March 31, 2014.

Just under 1,000 (994) of the study participants were diagnosed with mania or bipolar disorder, representing 10.9 per 1,000 person-years. All types of antidepressants taken by the patients were associated with an increased incidence of mania/bipolar disorder (unadjusted hazard ratio greater than 1.0 for all antidepressants), with incidence rates ranging from 13.1 (tricyclic antidepressants) to 19.1 (trazodone) per 1,000 person-years.

“Future research should not only focus on which classes of antidepressants are most associated with mania, but also on other associated factors in order to guide clinicians of the risk of mania in people with depression prior to prescribing antidepressant therapy,” the investigators noted. They disclosed having received research funding from various sources.

Read the full study in BMJ Open (doi: 10.1136/bmjopen-2015-008341).

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