ADHD, anxiety signal increased risk of bipolar disorder
Individuals with attention deficiency hyperactivity disorder (ADHD) or anxiety are at greater risk of developing bipolar disorder, according to a study. Moreover, the risk further increases in those who have received diagnoses of both ADHD and anxiety.
Researchers followed a birth cohort of 2,409,236 individuals born in Denmark. A total of 9,250 (mean age at onset 33.49 years) developed bipolar disorder over 37,394,865 person-years follow-up, corresponding to an incidence rate of 2.47 per 10,000 person-years.
The incidence rate of bipolar disorder per 10,000 person-years was 23.86 in individuals with a prior ADHD diagnosis only, 26.05 in those with prior anxiety only, 66.16 in those with prior diagnoses of both conditions, and 2.17 in those without prior ADHD and anxiety.
On Poisson regression analysis, a prior diagnosis of ADHD or anxiety increased the incidence of bipolar disorder up to tenfold (adjusted incidence rate ratio [IRR], 10.00; 95 percent CI, 8.58–11.57 and IRR, 9.61; 9.01–10.24, respectively; p<0.001 for both).
ADHD and anxiety exerted a joint effect, conferring a substantially greater risk when compared with either condition alone. The adjusted IRR for bipolar disorder was 21.15 (15.02–28.78; p<0.001) in the presence of both conditions.
According to researchers, the findings support the hypothesis that predisposition to bipolar disorder overlaps with both internalizing and externalizing psychopathology. As such, pre-emptive interventions may be considered in individuals with both ADHD and anxiety disorders to reduce the risk of bipolar disorder.