Hosang GM, Martin J, Karlsson R, et al. - Studies have revealed that there is a relatively common occurrence of subsyndromal hypomanic symptoms in the general population and the existence of its correlation with the onset of bipolar disorder (BD). Researchers herein examined a nonclinical youth sample to determine the genetic and environmental architecture of hypomanic symptoms and performed comparison of the estimates at varying severity levels and determined their correlation with diagnosed bipolar disorder.

• From the Child and Adolescent Twin Study in Sweden, researchers retrieve data for this cohort study of 8,568 twin pairs.

• Relative to female individuals, male individuals showed higher heritability estimates for hypomania.

• Hypomania and BD were identified to have moderate genetic and nonshared environmental correlations, and hypomania was noted to be significantly linked with the polygenic risk scores for schizophrenia and major depressive disorder but not for BD.

• Overall findings suggest that subsyndromal hypomania has etiology overlapping with BD, major depressive disorder, and schizophrenia, suggesting the possibility of it being a continuous trait for psychiatric disorders reflected at its extreme.