Taking some types of antidepressant may increase patients’ risk of mania and bipolar disorder, according to new UK research.
An analysis published in the online journal BMJ Open suggests the strongest link with serotonin reuptake inhibitors – known as SSRIs – and the dual action antidepressant venlafaxine.
“The association… highlights the importance of considering whether an individual with depression could be at high risk of future episodes of mania”
Researchers from King’s College London and South London and Maudsley NHS Foundation Trust examined the medical records of more than 21,000 adults treated for severe depression between 2006 and 2013.
They found treatment with certain antidepressants was linked to an increased risk of going on to be diagnosed with bipolar disorder or mania.
This link was particularly strong for SSRIs and venlafaxine, which were associated with around a 35% increased risk of bipolar disorder or mania.
However, the team said it was not possible to say whether taking the drugs might have caused these conditions to develop, adding their findings could simply be down to latent bipolar disorder that had yet to show up.
Even so, they concluded the observational study had important implications for mental health practice.
“The association of antidepressant therapy with mania highlights the importance of considering whether an individual who presents with depression could be at high risk of future episodes of mania,” they said.
“Our findings also highlight an ongoing need to develop better ways to predict future risk of mania in people with no prior history of bipolar disorder who present with an episode of depression,” they added.
The researchers went on to stress the overall risk of developing bipolar disorder was low and antidepressants were safe and effective treatments.