Methylphenidate monotherapy ups risk of mania in patients with bipolar disorder
There is no positive association between methylphenidate and treatment-emergent mania among patients with bipolar disorder simultaneously taking a mood-stabilizing medication, reports a new study. This is clinically important given that up to 20 percent of individuals with bipolar disorder have comorbid attention deficit hyperactivity disorder.
Researchers used linked Swedish national registries to identify adults (n=2,307) with bipolar disorder who initiated therapy with methylphenidate between 2006 and 2014. The participants were divided into those with and those without concomitant mood-stabilizing treatment.
Cox regression analyses were used to adjust for individual-specific confounders, including disorder severity, genetic makeup and early environmental factors, conditioning on individual to compare the mania rate (defined as hospitalization for mania or a new dispensation of stabilizing medication) 0 to 3 and 3 to 6 months after medication initiation following nontreated periods.
Methylphenidate monotherapy demonstrated an increased rate of manic episodes in patients within 3 months of medication start (hazard ratio [HR], 6.7; 95 percent CI, 2.0 to 22.4), with similar results for the subsequent 3 months.
In contrast, patients receiving mood stabilizers had lower risk of mania after starting methylphenidate (HR, 0.6; 0.4 to 0.9). There were similar results seen when only hospitalizations for mania were counted.
“Given the markedly increased hazard ratio of mania following methylphenidate initiation in bipolar patients not taking mood stabilizers, careful assessment to rule out bipolar disorder is indicated before initiating monotherapy with psychostimulants,” researchers said.
A national registry study found a similar result, in which antidepressant monotherapy correlated with an elevated mania risk. It added that there was no risk of mania in patients taking an antidepressant while treated with a mood stabilizer. These findings stressed the importance of avoiding antidepressant monotherapy in the treatment of bipolar disorder. [Am J Psychiatry 2014;171:1067-73]